* NAK new drivers without proper power management? @ 2007-02-09 21:57 Nigel Cunningham 2007-02-09 22:17 ` Arjan van de Ven 2007-02-10 3:42 ` Matthew Garrett 0 siblings, 2 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-09 21:57 UTC (permalink / raw) To: LKML Hi. I don't think this is already done (feel free to correct me if I'm wrong).. Can we start to NAK new drivers that don't have proper power management implemented? There really is no excuse for writing a new driver and not putting .suspend and .resume methods in anymore, is there? Regards, Nigel-getting-sick-of-drivers-without-pm-support Cunningham ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 21:57 NAK new drivers without proper power management? Nigel Cunningham @ 2007-02-09 22:17 ` Arjan van de Ven 2007-02-09 22:26 ` Nigel Cunningham 2007-02-10 19:38 ` Pavel Machek 2007-02-10 3:42 ` Matthew Garrett 1 sibling, 2 replies; 77+ messages in thread From: Arjan van de Ven @ 2007-02-09 22:17 UTC (permalink / raw) To: nigel; +Cc: LKML On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > Hi. > > I don't think this is already done (feel free to correct me if I'm > wrong).. > > Can we start to NAK new drivers that don't have proper power management > implemented? There really is no excuse for writing a new driver and not > putting .suspend and .resume methods in anymore, is there? to a large degree, a device driver that doesn't suspend is better than no device driver at all, right? now.. if you want to make the core warn about it, that's very fair ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:17 ` Arjan van de Ven @ 2007-02-09 22:26 ` Nigel Cunningham 2007-02-09 22:44 ` Rafael J. Wysocki ` (2 more replies) 2007-02-10 19:38 ` Pavel Machek 1 sibling, 3 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-09 22:26 UTC (permalink / raw) To: Arjan van de Ven; +Cc: LKML Hi. On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > Hi. > > > > I don't think this is already done (feel free to correct me if I'm > > wrong).. > > > > Can we start to NAK new drivers that don't have proper power management > > implemented? There really is no excuse for writing a new driver and not > > putting .suspend and .resume methods in anymore, is there? > > > to a large degree, a device driver that doesn't suspend is better than > no device driver at all, right? I'm not sure it is. It only makes more work for everyone else: We have to help people figure out what causes their computer to fail to resume (which can take quite a while), then get them them complain to driver author, and the driver author has to submit patches to fix it. All of this is avoided if they'll just do it right in the first place. > now.. if you want to make the core warn about it, that's very fair That's probably a good idea too, since I'm only suggesting this for new drivers. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:26 ` Nigel Cunningham @ 2007-02-09 22:44 ` Rafael J. Wysocki 2007-02-10 0:25 ` Jeff Garzik 2007-02-10 7:15 ` Arjan van de Ven 2 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-09 22:44 UTC (permalink / raw) To: nigel; +Cc: Arjan van de Ven, LKML, pm list On Friday, 9 February 2007 23:26, Nigel Cunningham wrote: > Hi. > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > > Hi. > > > > > > I don't think this is already done (feel free to correct me if I'm > > > wrong).. > > > > > > Can we start to NAK new drivers that don't have proper power management > > > implemented? There really is no excuse for writing a new driver and not > > > putting .suspend and .resume methods in anymore, is there? > > > > > > to a large degree, a device driver that doesn't suspend is better than > > no device driver at all, right? > > I'm not sure it is. It only makes more work for everyone else: We have > to help people figure out what causes their computer to fail to resume > (which can take quite a while), then get them them complain to driver > author, and the driver author has to submit patches to fix it. > > All of this is avoided if they'll just do it right in the first place. > > > now.. if you want to make the core warn about it, that's very fair > > That's probably a good idea too, since I'm only suggesting this for new > drivers. I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not having .suspend or .resume routines. Greetings, Rafael -- If you don't have the time to read, you don't have the time or the tools to write. - Stephen King ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? @ 2007-02-09 22:44 ` Rafael J. Wysocki 0 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-09 22:44 UTC (permalink / raw) To: nigel; +Cc: pm list, LKML, Arjan van de Ven On Friday, 9 February 2007 23:26, Nigel Cunningham wrote: > Hi. > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > > Hi. > > > > > > I don't think this is already done (feel free to correct me if I'm > > > wrong).. > > > > > > Can we start to NAK new drivers that don't have proper power management > > > implemented? There really is no excuse for writing a new driver and not > > > putting .suspend and .resume methods in anymore, is there? > > > > > > to a large degree, a device driver that doesn't suspend is better than > > no device driver at all, right? > > I'm not sure it is. It only makes more work for everyone else: We have > to help people figure out what causes their computer to fail to resume > (which can take quite a while), then get them them complain to driver > author, and the driver author has to submit patches to fix it. > > All of this is avoided if they'll just do it right in the first place. > > > now.. if you want to make the core warn about it, that's very fair > > That's probably a good idea too, since I'm only suggesting this for new > drivers. I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not having .suspend or .resume routines. Greetings, Rafael -- If you don't have the time to read, you don't have the time or the tools to write. - Stephen King ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:44 ` Rafael J. Wysocki @ 2007-02-09 22:51 ` Nigel Cunningham -1 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-09 22:51 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Arjan van de Ven, LKML, pm list Hi. On Fri, 2007-02-09 at 23:44 +0100, Rafael J. Wysocki wrote: > On Friday, 9 February 2007 23:26, Nigel Cunningham wrote: > > Hi. > > > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > > > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > > > Hi. > > > > > > > > I don't think this is already done (feel free to correct me if I'm > > > > wrong).. > > > > > > > > Can we start to NAK new drivers that don't have proper power management > > > > implemented? There really is no excuse for writing a new driver and not > > > > putting .suspend and .resume methods in anymore, is there? > > > > > > > > > to a large degree, a device driver that doesn't suspend is better than > > > no device driver at all, right? > > > > I'm not sure it is. It only makes more work for everyone else: We have > > to help people figure out what causes their computer to fail to resume > > (which can take quite a while), then get them them complain to driver > > author, and the driver author has to submit patches to fix it. > > > > All of this is avoided if they'll just do it right in the first place. > > > > > now.. if you want to make the core warn about it, that's very fair > > > > That's probably a good idea too, since I'm only suggesting this for new > > drivers. > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > having .suspend or .resume routines. The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. CONFIG_PM instead? Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? @ 2007-02-09 22:51 ` Nigel Cunningham 0 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-09 22:51 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: pm list, LKML, Arjan van de Ven Hi. On Fri, 2007-02-09 at 23:44 +0100, Rafael J. Wysocki wrote: > On Friday, 9 February 2007 23:26, Nigel Cunningham wrote: > > Hi. > > > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > > > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > > > Hi. > > > > > > > > I don't think this is already done (feel free to correct me if I'm > > > > wrong).. > > > > > > > > Can we start to NAK new drivers that don't have proper power management > > > > implemented? There really is no excuse for writing a new driver and not > > > > putting .suspend and .resume methods in anymore, is there? > > > > > > > > > to a large degree, a device driver that doesn't suspend is better than > > > no device driver at all, right? > > > > I'm not sure it is. It only makes more work for everyone else: We have > > to help people figure out what causes their computer to fail to resume > > (which can take quite a while), then get them them complain to driver > > author, and the driver author has to submit patches to fix it. > > > > All of this is avoided if they'll just do it right in the first place. > > > > > now.. if you want to make the core warn about it, that's very fair > > > > That's probably a good idea too, since I'm only suggesting this for new > > drivers. > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > having .suspend or .resume routines. The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. CONFIG_PM instead? Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:51 ` Nigel Cunningham @ 2007-02-09 23:12 ` Rafael J. Wysocki -1 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-09 23:12 UTC (permalink / raw) To: nigel; +Cc: Arjan van de Ven, LKML, pm list Hi, On Friday, 9 February 2007 23:51, Nigel Cunningham wrote: > Hi. > > On Fri, 2007-02-09 at 23:44 +0100, Rafael J. Wysocki wrote: > > On Friday, 9 February 2007 23:26, Nigel Cunningham wrote: > > > Hi. > > > > > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > > > > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > > > > Hi. > > > > > > > > > > I don't think this is already done (feel free to correct me if I'm > > > > > wrong).. > > > > > > > > > > Can we start to NAK new drivers that don't have proper power management > > > > > implemented? There really is no excuse for writing a new driver and not > > > > > putting .suspend and .resume methods in anymore, is there? > > > > > > > > > > > > to a large degree, a device driver that doesn't suspend is better than > > > > no device driver at all, right? > > > > > > I'm not sure it is. It only makes more work for everyone else: We have > > > to help people figure out what causes their computer to fail to resume > > > (which can take quite a while), then get them them complain to driver > > > author, and the driver author has to submit patches to fix it. > > > > > > All of this is avoided if they'll just do it right in the first place. > > > > > > > now.. if you want to make the core warn about it, that's very fair > > > > > > That's probably a good idea too, since I'm only suggesting this for new > > > drivers. > > > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > > having .suspend or .resume routines. > > The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. > CONFIG_PM instead? Well, I can imagine a driver that doesn't need a .suspend routine, for example, and I don't think we should make the kernel always complain about that. I think if someone doesn't set CONFIG_PM_DEBUG, we can ask him to set it and report back. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? @ 2007-02-09 23:12 ` Rafael J. Wysocki 0 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-09 23:12 UTC (permalink / raw) To: nigel; +Cc: pm list, LKML, Arjan van de Ven Hi, On Friday, 9 February 2007 23:51, Nigel Cunningham wrote: > Hi. > > On Fri, 2007-02-09 at 23:44 +0100, Rafael J. Wysocki wrote: > > On Friday, 9 February 2007 23:26, Nigel Cunningham wrote: > > > Hi. > > > > > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > > > > On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > > > > > Hi. > > > > > > > > > > I don't think this is already done (feel free to correct me if I'm > > > > > wrong).. > > > > > > > > > > Can we start to NAK new drivers that don't have proper power management > > > > > implemented? There really is no excuse for writing a new driver and not > > > > > putting .suspend and .resume methods in anymore, is there? > > > > > > > > > > > > to a large degree, a device driver that doesn't suspend is better than > > > > no device driver at all, right? > > > > > > I'm not sure it is. It only makes more work for everyone else: We have > > > to help people figure out what causes their computer to fail to resume > > > (which can take quite a while), then get them them complain to driver > > > author, and the driver author has to submit patches to fix it. > > > > > > All of this is avoided if they'll just do it right in the first place. > > > > > > > now.. if you want to make the core warn about it, that's very fair > > > > > > That's probably a good idea too, since I'm only suggesting this for new > > > drivers. > > > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > > having .suspend or .resume routines. > > The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. > CONFIG_PM instead? Well, I can imagine a driver that doesn't need a .suspend routine, for example, and I don't think we should make the kernel always complain about that. I think if someone doesn't set CONFIG_PM_DEBUG, we can ask him to set it and report back. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 23:12 ` Rafael J. Wysocki @ 2007-02-09 23:28 ` Nigel Cunningham -1 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-09 23:28 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Arjan van de Ven, LKML, pm list Hi. On Sat, 2007-02-10 at 00:12 +0100, Rafael J. Wysocki wrote: > > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > > > having .suspend or .resume routines. > > > > The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. > > CONFIG_PM instead? > > Well, I can imagine a driver that doesn't need a .suspend routine, for example, > and I don't think we should make the kernel always complain about that. How about... #ifdef CONFIG_PM_PARANOIA static int empty_suspend_routine(struct device *dev, pm_message_t state) { return 0; } #define empty_suspend empty_suspend_routine #else #define empty_suspend NULL #endif ... .suspend = empty_suspend; ... Then CONFIG_PM_PARANOIA can be enabled by default for now, and when we eventually device it's not needed anymore, someone can submit a patch replacing either turning off the CONFIG by default or removing the whole mechanism. > I think if someone doesn't set CONFIG_PM_DEBUG, we can ask him to set it > and report back. We can, but the whole point to the suggestion was to make your life and mine easier, as well as those of our users. Making it dependent on CONFIG_PM instead achieves that by: - Saving you, I and distro people from having to tell their users to enable the option (and how to) - Saving the users the problem of going through all the steps, making mistakes, potentially ending up with unbootable systems because they make mistakes and so on. This way, they just need to look in dmesg. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? @ 2007-02-09 23:28 ` Nigel Cunningham 0 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-09 23:28 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: pm list, LKML, Arjan van de Ven Hi. On Sat, 2007-02-10 at 00:12 +0100, Rafael J. Wysocki wrote: > > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > > > having .suspend or .resume routines. > > > > The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. > > CONFIG_PM instead? > > Well, I can imagine a driver that doesn't need a .suspend routine, for example, > and I don't think we should make the kernel always complain about that. How about... #ifdef CONFIG_PM_PARANOIA static int empty_suspend_routine(struct device *dev, pm_message_t state) { return 0; } #define empty_suspend empty_suspend_routine #else #define empty_suspend NULL #endif ... .suspend = empty_suspend; ... Then CONFIG_PM_PARANOIA can be enabled by default for now, and when we eventually device it's not needed anymore, someone can submit a patch replacing either turning off the CONFIG by default or removing the whole mechanism. > I think if someone doesn't set CONFIG_PM_DEBUG, we can ask him to set it > and report back. We can, but the whole point to the suggestion was to make your life and mine easier, as well as those of our users. Making it dependent on CONFIG_PM instead achieves that by: - Saving you, I and distro people from having to tell their users to enable the option (and how to) - Saving the users the problem of going through all the steps, making mistakes, potentially ending up with unbootable systems because they make mistakes and so on. This way, they just need to look in dmesg. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 23:28 ` Nigel Cunningham @ 2007-02-10 0:12 ` Rafael J. Wysocki -1 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-10 0:12 UTC (permalink / raw) To: nigel; +Cc: Arjan van de Ven, LKML, pm list On Saturday, 10 February 2007 00:28, Nigel Cunningham wrote: > Hi. > > On Sat, 2007-02-10 at 00:12 +0100, Rafael J. Wysocki wrote: > > > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > > > > having .suspend or .resume routines. > > > > > > The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. > > > CONFIG_PM instead? > > > > Well, I can imagine a driver that doesn't need a .suspend routine, for example, > > and I don't think we should make the kernel always complain about that. > > How about... > > #ifdef CONFIG_PM_PARANOIA > static int empty_suspend_routine(struct device *dev, pm_message_t state) > { > return 0; > } > #define empty_suspend empty_suspend_routine > #else > #define empty_suspend NULL > #endif > > ... > > .suspend = empty_suspend; > ... > > > Then CONFIG_PM_PARANOIA can be enabled by default for now, and when we > eventually device it's not needed anymore, someone can submit a patch > replacing either turning off the CONFIG by default or removing the whole > mechanism. I think that would be tempting people to abuse it, for example by defining or undefining things just to quieten the warning. In my opinion the only way to make the warning go away should be to define a non-NULL .suspend (.resume) routine and that's why I don't think the warning should be mandatory. > > I think if someone doesn't set CONFIG_PM_DEBUG, we can ask him to set it > > and report back. > > We can, but the whole point to the suggestion was to make your life and > mine easier, as well as those of our users. > > Making it dependent on CONFIG_PM instead achieves that by: > - Saving you, I and distro people from having to tell their users to > enable the option (and how to) I think the distro people can patch their kernels to fit their needs. > - Saving the users the problem of going through all the steps, making > mistakes, potentially ending up with unbootable systems because they > make mistakes and so on. > > This way, they just need to look in dmesg. Well, IMO, if someone doesn't know how to compile and install the kernel, he'll be using a distro kernel anyway and then see above. Otherwise we can safely ask him to turn on whatever debugging options we need. Greetings, Rafael -- If you don't have the time to read, you don't have the time or the tools to write. - Stephen King ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? @ 2007-02-10 0:12 ` Rafael J. Wysocki 0 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-10 0:12 UTC (permalink / raw) To: nigel; +Cc: pm list, LKML, Arjan van de Ven On Saturday, 10 February 2007 00:28, Nigel Cunningham wrote: > Hi. > > On Sat, 2007-02-10 at 00:12 +0100, Rafael J. Wysocki wrote: > > > > I think if CONFIG_PM_DEBUG is set, the core should warn about drivers not > > > > having .suspend or .resume routines. > > > > > > The only problem with that is, not everyone turns on CONFIG_PM_DEBUG. > > > CONFIG_PM instead? > > > > Well, I can imagine a driver that doesn't need a .suspend routine, for example, > > and I don't think we should make the kernel always complain about that. > > How about... > > #ifdef CONFIG_PM_PARANOIA > static int empty_suspend_routine(struct device *dev, pm_message_t state) > { > return 0; > } > #define empty_suspend empty_suspend_routine > #else > #define empty_suspend NULL > #endif > > ... > > .suspend = empty_suspend; > ... > > > Then CONFIG_PM_PARANOIA can be enabled by default for now, and when we > eventually device it's not needed anymore, someone can submit a patch > replacing either turning off the CONFIG by default or removing the whole > mechanism. I think that would be tempting people to abuse it, for example by defining or undefining things just to quieten the warning. In my opinion the only way to make the warning go away should be to define a non-NULL .suspend (.resume) routine and that's why I don't think the warning should be mandatory. > > I think if someone doesn't set CONFIG_PM_DEBUG, we can ask him to set it > > and report back. > > We can, but the whole point to the suggestion was to make your life and > mine easier, as well as those of our users. > > Making it dependent on CONFIG_PM instead achieves that by: > - Saving you, I and distro people from having to tell their users to > enable the option (and how to) I think the distro people can patch their kernels to fit their needs. > - Saving the users the problem of going through all the steps, making > mistakes, potentially ending up with unbootable systems because they > make mistakes and so on. > > This way, they just need to look in dmesg. Well, IMO, if someone doesn't know how to compile and install the kernel, he'll be using a distro kernel anyway and then see above. Otherwise we can safely ask him to turn on whatever debugging options we need. Greetings, Rafael -- If you don't have the time to read, you don't have the time or the tools to write. - Stephen King ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:26 ` Nigel Cunningham 2007-02-09 22:44 ` Rafael J. Wysocki @ 2007-02-10 0:25 ` Jeff Garzik 2007-02-10 6:43 ` Willy Tarreau 2007-02-10 7:15 ` Arjan van de Ven 2 siblings, 1 reply; 77+ messages in thread From: Jeff Garzik @ 2007-02-10 0:25 UTC (permalink / raw) To: nigel; +Cc: Arjan van de Ven, LKML Nigel Cunningham wrote: > Hi. > > On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: >> On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: >>> Hi. >>> >>> I don't think this is already done (feel free to correct me if I'm >>> wrong).. >>> >>> Can we start to NAK new drivers that don't have proper power management >>> implemented? There really is no excuse for writing a new driver and not >>> putting .suspend and .resume methods in anymore, is there? >> >> to a large degree, a device driver that doesn't suspend is better than >> no device driver at all, right? > > I'm not sure it is. It only makes more work for everyone else: We have > to help people figure out what causes their computer to fail to resume > (which can take quite a while), then get them them complain to driver > author, and the driver author has to submit patches to fix it. > > All of this is avoided if they'll just do it right in the first place. A lot of a lot of things could have been avoided, if they just did it right the first time. I think it's more valuable to users to get a basic network driver that pings or a basic ATA driver that reads/writes, than peripheral issues like suspend/resume. Certainly we should ask for it, but it shouldn't be a merge-stopper. Jeff ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 0:25 ` Jeff Garzik @ 2007-02-10 6:43 ` Willy Tarreau 2007-02-10 23:52 ` Tilman Schmidt 0 siblings, 1 reply; 77+ messages in thread From: Willy Tarreau @ 2007-02-10 6:43 UTC (permalink / raw) To: Jeff Garzik; +Cc: nigel, Arjan van de Ven, LKML On Fri, Feb 09, 2007 at 07:25:34PM -0500, Jeff Garzik wrote: > Nigel Cunningham wrote: > >Hi. > > > >On Fri, 2007-02-09 at 23:17 +0100, Arjan van de Ven wrote: > >>On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: > >>>Hi. > >>> > >>>I don't think this is already done (feel free to correct me if I'm > >>>wrong).. > >>> > >>>Can we start to NAK new drivers that don't have proper power management > >>>implemented? There really is no excuse for writing a new driver and not > >>>putting .suspend and .resume methods in anymore, is there? > >> > >>to a large degree, a device driver that doesn't suspend is better than > >>no device driver at all, right? > > > >I'm not sure it is. It only makes more work for everyone else: We have > >to help people figure out what causes their computer to fail to resume > >(which can take quite a while), then get them them complain to driver > >author, and the driver author has to submit patches to fix it. > > > >All of this is avoided if they'll just do it right in the first place. > > A lot of a lot of things could have been avoided, if they just did it > right the first time. > > I think it's more valuable to users to get a basic network driver that > pings or a basic ATA driver that reads/writes, than peripheral issues > like suspend/resume. 100% agreed. I've been used to a notebook (VAIO) which did not correctly shut down, and did not support reboot. Now the one I have behaves normally on both features. I've never ever felt the need for suspend/resume, that I've always attributed to "geeks" requirements. I had to debug the shutdown code myself for the previous notebook, and discovered that it was caused by bugs in the ACPI state transitions for suspend and such fancy features. I would really have prefered that the people writing the ACPI code had focused first on power-on/ power-off before the rest. > Certainly we should ask for it, but it shouldn't be a merge-stopper. I think we should even proceed in the opposite direction : refuse to suspend if at least one driver does not support the feature, and enumerate the faulty drivers on the console. While I agree that a machine which resumes in a bad state is not funny at all to debug, at least when the user expects his notebook to suspend and sees that it refuses, he can complain about the drivers which do not support it, and can even unload them first if unneeded. Regards, Willy ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 6:43 ` Willy Tarreau @ 2007-02-10 23:52 ` Tilman Schmidt 0 siblings, 0 replies; 77+ messages in thread From: Tilman Schmidt @ 2007-02-10 23:52 UTC (permalink / raw) To: Willy Tarreau; +Cc: Jeff Garzik, nigel, Arjan van de Ven, LKML [-- Attachment #1: Type: text/plain, Size: 1073 bytes --] Am 10.02.2007 07:43 schrieb Willy Tarreau: > On Fri, Feb 09, 2007 at 07:25:34PM -0500, Jeff Garzik wrote: >>>> On Sat, 2007-02-10 at 08:57 +1100, Nigel Cunningham wrote: >>>>> Can we start to NAK new drivers that don't have proper power management >>>>> implemented? [...] >> Certainly we should ask for it, but it shouldn't be a merge-stopper. > > I think we should even proceed in the opposite direction : refuse to suspend > if at least one driver does not support the feature, and enumerate the > faulty drivers on the console. While I agree that a machine which resumes > in a bad state is not funny at all to debug, at least when the user expects > his notebook to suspend and sees that it refuses, he can complain about the > drivers which do not support it, and can even unload them first if unneeded. I agree wholeheartedly. That's the correct way to handle this. -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany - In theory, there is no difference between theory and practice. In practice, there is. [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 253 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:26 ` Nigel Cunningham 2007-02-09 22:44 ` Rafael J. Wysocki 2007-02-10 0:25 ` Jeff Garzik @ 2007-02-10 7:15 ` Arjan van de Ven 2 siblings, 0 replies; 77+ messages in thread From: Arjan van de Ven @ 2007-02-10 7:15 UTC (permalink / raw) To: nigel; +Cc: LKML > > > > to a large degree, a device driver that doesn't suspend is better than > > no device driver at all, right? > > I'm not sure it is. It only makes more work for everyone else: We have > to help people figure out what causes their computer to fail to resume > (which can take quite a while), so we make the kernel printk on suspend if there are devices without suspend/resume. Heck, make a config option that prints that at modprobe time. -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 22:17 ` Arjan van de Ven 2007-02-09 22:26 ` Nigel Cunningham @ 2007-02-10 19:38 ` Pavel Machek 2007-02-10 22:20 ` Rafael J. Wysocki 1 sibling, 1 reply; 77+ messages in thread From: Pavel Machek @ 2007-02-10 19:38 UTC (permalink / raw) To: Arjan van de Ven; +Cc: nigel, LKML Hi! > > I don't think this is already done (feel free to correct me if I'm > > wrong).. > > > > Can we start to NAK new drivers that don't have proper power management > > implemented? There really is no excuse for writing a new driver and not > > putting .suspend and .resume methods in anymore, is there? > > to a large degree, a device driver that doesn't suspend is better than > no device driver at all, right? > now.. if you want to make the core warn about it, that's very fair Well, driver that is broken on SMP is arguably better than no driver at all, yet we'd probably avoid merging that. It would be nice to start including suspend in 'must work' list... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 19:38 ` Pavel Machek @ 2007-02-10 22:20 ` Rafael J. Wysocki 2007-02-10 22:37 ` Nigel Cunningham ` (2 more replies) 0 siblings, 3 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-10 22:20 UTC (permalink / raw) To: Pavel Machek; +Cc: Arjan van de Ven, nigel, LKML Hi, On Saturday, 10 February 2007 20:38, Pavel Machek wrote: > Hi! > > > > I don't think this is already done (feel free to correct me if I'm > > > wrong).. > > > > > > Can we start to NAK new drivers that don't have proper power management > > > implemented? There really is no excuse for writing a new driver and not > > > putting .suspend and .resume methods in anymore, is there? > > > > to a large degree, a device driver that doesn't suspend is better than > > no device driver at all, right? > > now.. if you want to make the core warn about it, that's very fair > > Well, driver that is broken on SMP is arguably better than no driver > at all, yet we'd probably avoid merging that. It would be nice to > start including suspend in 'must work' list... What about this: "If the device requires that, implement .suspend and .resume or at least define .suspend that will always return -ENOSYS (then people will know they have to unload the driver before the suspend). Similarly, if you aren't sure whether or not the device requires .suspend and .resume, define .suspend that will always return -ENOSYS." Greetings, Rafael -- If you don't have the time to read, you don't have the time or the tools to write. - Stephen King ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 22:20 ` Rafael J. Wysocki @ 2007-02-10 22:37 ` Nigel Cunningham 2007-02-10 23:45 ` Tilman Schmidt 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau 2007-02-11 19:42 ` Pavel Machek 2007-02-12 8:49 ` Geert Uytterhoeven 2 siblings, 2 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-10 22:37 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Pavel Machek, Arjan van de Ven, LKML Hi. On Sat, 2007-02-10 at 23:20 +0100, Rafael J. Wysocki wrote: > Hi, > > On Saturday, 10 February 2007 20:38, Pavel Machek wrote: > > Hi! > > > > > > I don't think this is already done (feel free to correct me if I'm > > > > wrong).. > > > > > > > > Can we start to NAK new drivers that don't have proper power management > > > > implemented? There really is no excuse for writing a new driver and not > > > > putting .suspend and .resume methods in anymore, is there? > > > > > > to a large degree, a device driver that doesn't suspend is better than > > > no device driver at all, right? > > > now.. if you want to make the core warn about it, that's very fair > > > > Well, driver that is broken on SMP is arguably better than no driver > > at all, yet we'd probably avoid merging that. It would be nice to > > start including suspend in 'must work' list... > > What about this: > > "If the device requires that, implement .suspend and .resume or at least > define .suspend that will always return -ENOSYS (then people will know they > have to unload the driver before the suspend). Similarly, if you aren't sure > whether or not the device requires .suspend and .resume, define .suspend that > will always return -ENOSYS." If your device requires power management, and you know it requires power management, why not just implement power management? Doing -ENOSYS instead is like saying -ESPAMMEBECAUSEIMLAZY. Let me put it another way: People keep talking about Linux being ready for the desktop. To me at least (but I dare say for lots of other people too), being ready for the desktop means that things just work, without having to recompile kernels or bug driver authors or wait twelve months. And it means that doing a bare minimum isn't enough. We keep claiming that Open Source is better than Proprietary software. If we accept half-pie jobs of implementing support for anything - driver power management support or hibernation support or whatever - as 'good enough', we're undercutting that argument. Linux's power management support should - as far as we're able - be at least as good as that other operating system's and preferably way, way better. -ENOSYS is just not acceptable. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 22:37 ` Nigel Cunningham @ 2007-02-10 23:45 ` Tilman Schmidt 2007-02-11 0:27 ` Rafael J. Wysocki 2007-02-11 22:37 ` Nigel Cunningham 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau 1 sibling, 2 replies; 77+ messages in thread From: Tilman Schmidt @ 2007-02-10 23:45 UTC (permalink / raw) To: nigel; +Cc: Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML [-- Attachment #1: Type: text/plain, Size: 2364 bytes --] Am 10.02.2007 23:37 schrieb Nigel Cunningham: > If your device requires power management, and you know it requires power > management, why not just implement power management? Doing -ENOSYS > instead is like saying -ESPAMMEBECAUSEIMLAZY. Like it or not, power management is far from trivial, and people writing device drivers have limited resources. Calling them lazy does not help that in the least. If you try to put pressure on them by refusing to merge their work as long as it doesn't provide this or that functionality, you *may* end up with a few drivers having that functionality which otherwise wouldn't, but you *will* also end up with a number of drivers never making it into the kernel because their authors just have to give up. Also, in your argument you neglected a few cases: - What if my device does not require power management? - What if I don't know whether my device requires power management? - What if I know my device would require power management, but don't know how to implement it? > Let me put it another way: People keep talking about Linux being ready > for the desktop. To me at least (but I dare say for lots of other people > too), being ready for the desktop means that things just work, without > having to recompile kernels or bug driver authors or wait twelve > months. Exactly. > And it means that doing a bare minimum isn't enough. We keep claiming > that Open Source is better than Proprietary software. If we accept > half-pie jobs of implementing support for anything - driver power > management support or hibernation support or whatever - as 'good > enough', we're undercutting that argument. Linux's power management > support should - as far as we're able - be at least as good as that > other operating system's and preferably way, way better. > > -ENOSYS is just not acceptable. Your argument falls down the moment you consider the alternative: not merging the driver means that the device won't work at all. (Given that out-of-tree drivers are actively discouraged, to put it mildly.) That's arguably farther from "desktop readiness" than a device not supporting power management. -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany - In theory, there is no difference between theory and practice. In practice, there is. [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 253 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 23:45 ` Tilman Schmidt @ 2007-02-11 0:27 ` Rafael J. Wysocki 2007-02-11 22:41 ` Nigel Cunningham 2007-02-11 22:37 ` Nigel Cunningham 1 sibling, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-11 0:27 UTC (permalink / raw) To: Tilman Schmidt; +Cc: nigel, Pavel Machek, Arjan van de Ven, LKML On Sunday, 11 February 2007 00:45, Tilman Schmidt wrote: > Am 10.02.2007 23:37 schrieb Nigel Cunningham: > > If your device requires power management, and you know it requires power > > management, why not just implement power management? Doing -ENOSYS > > instead is like saying -ESPAMMEBECAUSEIMLAZY. > > Like it or not, power management is far from trivial, and people > writing device drivers have limited resources. Calling them lazy > does not help that in the least. If you try to put pressure on them > by refusing to merge their work as long as it doesn't provide this > or that functionality, you *may* end up with a few drivers having > that functionality which otherwise wouldn't, but you *will* also > end up with a number of drivers never making it into the kernel > because their authors just have to give up. > > Also, in your argument you neglected a few cases: > - What if my device does not require power management? > - What if I don't know whether my device requires power management? > - What if I know my device would require power management, but don't > know how to implement it? Plus: - What if I'm planning to implement the power managemet, but not just right now? > > Let me put it another way: People keep talking about Linux being ready > > for the desktop. To me at least (but I dare say for lots of other people > > too), being ready for the desktop means that things just work, without > > having to recompile kernels or bug driver authors or wait twelve > > months. > > Exactly. > > > And it means that doing a bare minimum isn't enough. We keep claiming > > that Open Source is better than Proprietary software. If we accept > > half-pie jobs of implementing support for anything - driver power > > management support or hibernation support or whatever - as 'good > > enough', we're undercutting that argument. Linux's power management > > support should - as far as we're able - be at least as good as that > > other operating system's and preferably way, way better. > > > > -ENOSYS is just not acceptable. > > Your argument falls down the moment you consider the alternative: > not merging the driver means that the device won't work at all. > (Given that out-of-tree drivers are actively discouraged, to put > it mildly.) That's arguably farther from "desktop readiness" than > a device not supporting power management. Agreed. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 0:27 ` Rafael J. Wysocki @ 2007-02-11 22:41 ` Nigel Cunningham 2007-02-13 15:55 ` Mark Lord 0 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 22:41 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Tilman Schmidt, Pavel Machek, Arjan van de Ven, LKML On Sun, 2007-02-11 at 01:27 +0100, Rafael J. Wysocki wrote: > On Sunday, 11 February 2007 00:45, Tilman Schmidt wrote: > > Am 10.02.2007 23:37 schrieb Nigel Cunningham: > > > If your device requires power management, and you know it requires power > > > management, why not just implement power management? Doing -ENOSYS > > > instead is like saying -ESPAMMEBECAUSEIMLAZY. > > > > Like it or not, power management is far from trivial, and people > > writing device drivers have limited resources. Calling them lazy > > does not help that in the least. If you try to put pressure on them > > by refusing to merge their work as long as it doesn't provide this > > or that functionality, you *may* end up with a few drivers having > > that functionality which otherwise wouldn't, but you *will* also > > end up with a number of drivers never making it into the kernel > > because their authors just have to give up. > > > > Also, in your argument you neglected a few cases: > > - What if my device does not require power management? > > - What if I don't know whether my device requires power management? > > - What if I know my device would require power management, but don't > > know how to implement it? > > Plus: > - What if I'm planning to implement the power managemet, but not just right > now? Why not right now? Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 22:41 ` Nigel Cunningham @ 2007-02-13 15:55 ` Mark Lord 2007-02-13 16:06 ` Christoph Hellwig 0 siblings, 1 reply; 77+ messages in thread From: Mark Lord @ 2007-02-13 15:55 UTC (permalink / raw) To: nigel Cc: Rafael J. Wysocki, Tilman Schmidt, Pavel Machek, Arjan van de Ven, LKML Nigel Cunningham wrote: > On Sun, 2007-02-11 at 01:27 +0100, Rafael J. Wysocki wrote: >> Plus: >> - What if I'm planning to implement the power managemet, but not just right >> now? > > Why not right now? LKML is much more receptive to drivers that follow the "release early, release often" mantra. Which means we really have to be more accomodating of drivers that start out simple, and then gain all of the non-essential capabilities gradually over time. Simple observation here shows much more hostility :) to drivers that are simply "presented" as a complete whole. Often for good reason -- starting out with a framework and then adding the rest bit by bit allows for much better peer review and feedback. And not all devices / situations need power management, and lack of documentation on the hardware often prevents us from implementing it at the outset. Cheers ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-13 15:55 ` Mark Lord @ 2007-02-13 16:06 ` Christoph Hellwig 0 siblings, 0 replies; 77+ messages in thread From: Christoph Hellwig @ 2007-02-13 16:06 UTC (permalink / raw) To: Mark Lord Cc: nigel, Rafael J. Wysocki, Tilman Schmidt, Pavel Machek, Arjan van de Ven, LKML On Tue, Feb 13, 2007 at 10:55:18AM -0500, Mark Lord wrote: > LKML is much more receptive to drivers that follow > the "release early, release often" mantra. Exactly. > Which means we really have to be more accomodating of > drivers that start out simple, and then gain all of the > non-essential capabilities gradually over time. We usually are, the endless flamewar lurkers might not :) > > Simple observation here shows much more hostility :) > to drivers that are simply "presented" as a complete whole. > Often for good reason -- starting out with a framework > and then adding the rest bit by bit allows for much better > peer review and feedback. *nod* > And not all devices / situations need power management, > and lack of documentation on the hardware often prevents > us from implementing it at the outset. *nod* So can be use Mark's excellent post as closing of this utterly useless thread and go on to real work now? ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 23:45 ` Tilman Schmidt 2007-02-11 0:27 ` Rafael J. Wysocki @ 2007-02-11 22:37 ` Nigel Cunningham 2007-02-12 0:10 ` Tilman Schmidt 1 sibling, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 22:37 UTC (permalink / raw) To: Tilman Schmidt; +Cc: Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML Hi. On Sun, 2007-02-11 at 00:45 +0100, Tilman Schmidt wrote: > Am 10.02.2007 23:37 schrieb Nigel Cunningham: > > If your device requires power management, and you know it requires power > > management, why not just implement power management? Doing -ENOSYS > > instead is like saying -ESPAMMEBECAUSEIMLAZY. > > Like it or not, power management is far from trivial, and people > writing device drivers have limited resources. Calling them lazy > does not help that in the least. If you try to put pressure on them > by refusing to merge their work as long as it doesn't provide this > or that functionality, you *may* end up with a few drivers having > that functionality which otherwise wouldn't, but you *will* also > end up with a number of drivers never making it into the kernel > because their authors just have to give up. It's not that complex. All we're really talking about is a bit of extra code to cleanup and configure hardware state; things that the driver author already knows how to do. S3 might require a bit more initialisation if firmware needs to be reloaded or more extensive configuration needs to be done, but if there's firmware to be loaded, there is a reasonably good probability that we loaded it from Linux to start with anyway. > Also, in your argument you neglected a few cases: > - What if my device does not require power management? Then you as a generic routine that does nothing but return success (potentially shared with other drivers that are in the same situation). > - What if I don't know whether my device requires power management? The questions are straight forward: Is there hardware state that needs to be configured if you've just booted the computer and nothing else has touched it? If so, that needs to be done in a resume method. Do you need to clean up state prior to doing the things in the resume method, or otherwise do things to quiesce the driver? If so, they will need to be done in the suspend method. The result will be roughly similar to what you do for module load/unload, except maybe less complete in some cases. > - What if I know my device would require power management, but don't > know how to implement it? I've just told you above :) Now you know! > > Let me put it another way: People keep talking about Linux being ready > > for the desktop. To me at least (but I dare say for lots of other people > > too), being ready for the desktop means that things just work, without > > having to recompile kernels or bug driver authors or wait twelve > > months. > > Exactly. > > > And it means that doing a bare minimum isn't enough. We keep claiming > > that Open Source is better than Proprietary software. If we accept > > half-pie jobs of implementing support for anything - driver power > > management support or hibernation support or whatever - as 'good > > enough', we're undercutting that argument. Linux's power management > > support should - as far as we're able - be at least as good as that > > other operating system's and preferably way, way better. > > > > -ENOSYS is just not acceptable. > > Your argument falls down the moment you consider the alternative: > not merging the driver means that the device won't work at all. > (Given that out-of-tree drivers are actively discouraged, to put > it mildly.) That's arguably farther from "desktop readiness" than > a device not supporting power management. I disagree (but I would, of course!). If we apply your logic consistently, we should merge the driver as soon as any code is written for it (anything is better than nothing). I'm simply arguing that a driver that handling suspend and resume should be as much of a requirement as not causing memory corruption or such like are. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 22:37 ` Nigel Cunningham @ 2007-02-12 0:10 ` Tilman Schmidt 2007-02-12 0:20 ` Rafael J. Wysocki ` (2 more replies) 0 siblings, 3 replies; 77+ messages in thread From: Tilman Schmidt @ 2007-02-12 0:10 UTC (permalink / raw) To: nigel; +Cc: Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML [-- Attachment #1: Type: text/plain, Size: 4387 bytes --] Hi, Am 11.02.2007 23:37 schrieb Nigel Cunningham: > On Sun, 2007-02-11 at 00:45 +0100, Tilman Schmidt wrote: >> Am 10.02.2007 23:37 schrieb Nigel Cunningham: >>> If your device requires power management, and you know it requires power >>> management, why not just implement power management? [...] >> Like it or not, power management is far from trivial, and people >> writing device drivers have limited resources. [...] > It's not that complex. All we're really talking about is a bit of extra > code to cleanup and configure hardware state; things that the driver > author already knows how to do. S3 might require a bit more > initialisation if firmware needs to be reloaded or more extensive > configuration needs to be done, but if there's firmware to be loaded, > there is a reasonably good probability that we loaded it from Linux to > start with anyway. You are assuming a perfect world where driver authors have complete knowledge of their devices. In reality, many drivers (including those I have the mixed pleasure of maintaining) are based at least in part on reverse engineering, and managing power states may well fall into the domain of things not yet sufficiently reverse engineered. >> Also, in your argument you neglected a few cases: >> - What if my device does not require power management? > > Then you as a generic routine that does nothing but return success > (potentially shared with other drivers that are in the same situation). But if I just write an empty routine like that I open myself up to criticism along the lines of "writing dummy routines just in order to shut up kernel warnings". BTDT. >> - What if I don't know whether my device requires power management? > > The questions are straight forward: Is there hardware state that needs > to be configured if you've just booted the computer and nothing else has > touched it? If so, that needs to be done in a resume method. Do you need > to clean up state prior to doing the things in the resume method, or > otherwise do things to quiesce the driver? If so, they will need to be > done in the suspend method. The result will be roughly similar to what > you do for module load/unload, except maybe less complete in some cases. I don't doubt your basic assessment. However it doesn't translate that easily into a real implementation. In my case, I maintain a USB driver, so I have to deal with USB specifics of suspend/resume which happen not to be that well documented. My driver provides an isdn4linux device but isdn4linux knows nothing about suspend/resume so I am on my own on how to reconcile the two. The device itself, though in turn far from trivial, is actually the least of my worries. >> - What if I know my device would require power management, but don't >> know how to implement it? > > I've just told you above :) Now you know! No I don't. See above. >>> -ENOSYS is just not acceptable. >> Your argument falls down the moment you consider the alternative: >> not merging the driver means that the device won't work at all. >> (Given that out-of-tree drivers are actively discouraged, to put >> it mildly.) That's arguably farther from "desktop readiness" than >> a device not supporting power management. > > I disagree (but I would, of course!). If we apply your logic > consistently, we should merge the driver as soon as any code is written > for it (anything is better than nothing). I'm simply arguing that a > driver that handling suspend and resume should be as much of a > requirement as not causing memory corruption or such like are. Well, that's a common fallacy about applying any logic consistently. There's a continuum of usefulness from "hardly works at all" through "causes random memory corruption", "doesn't support power management", and "does not support some esoteric protocol variety no one ever heard of anyways" up to "supports any and all uses to which anyone could possibly want to put the device". I would argue that "doesn't support power management" is *much* farther up that ladder than, for example, "causes random memory corruption". Regards, Tilman -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite) [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 253 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 0:10 ` Tilman Schmidt @ 2007-02-12 0:20 ` Rafael J. Wysocki 2007-02-12 4:08 ` Nigel Cunningham 2007-03-03 22:48 ` Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) Tilman Schmidt 2 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 0:20 UTC (permalink / raw) To: Tilman Schmidt; +Cc: nigel, Pavel Machek, Arjan van de Ven, LKML Hi, On Monday, 12 February 2007 01:10, Tilman Schmidt wrote: > Hi, > > Am 11.02.2007 23:37 schrieb Nigel Cunningham: > > On Sun, 2007-02-11 at 00:45 +0100, Tilman Schmidt wrote: > >> Am 10.02.2007 23:37 schrieb Nigel Cunningham: > >>> If your device requires power management, and you know it requires power > >>> management, why not just implement power management? [...] > >> Like it or not, power management is far from trivial, and people > >> writing device drivers have limited resources. [...] > > It's not that complex. All we're really talking about is a bit of extra > > code to cleanup and configure hardware state; things that the driver > > author already knows how to do. S3 might require a bit more > > initialisation if firmware needs to be reloaded or more extensive > > configuration needs to be done, but if there's firmware to be loaded, > > there is a reasonably good probability that we loaded it from Linux to > > start with anyway. > > You are assuming a perfect world where driver authors have complete > knowledge of their devices. In reality, many drivers (including > those I have the mixed pleasure of maintaining) are based at least > in part on reverse engineering, and managing power states may well > fall into the domain of things not yet sufficiently reverse > engineered. Exactly. > >> Also, in your argument you neglected a few cases: > >> - What if my device does not require power management? > > > > Then you as a generic routine that does nothing but return success > > (potentially shared with other drivers that are in the same situation). > > But if I just write an empty routine like that I open myself up to > criticism along the lines of "writing dummy routines just in order > to shut up kernel warnings". BTDT. Well, for me the design that required driver authors to write empty routines returning success, would be bad. > >> - What if I don't know whether my device requires power management? > > > > The questions are straight forward: Is there hardware state that needs > > to be configured if you've just booted the computer and nothing else has > > touched it? If so, that needs to be done in a resume method. Do you need > > to clean up state prior to doing the things in the resume method, or > > otherwise do things to quiesce the driver? If so, they will need to be > > done in the suspend method. The result will be roughly similar to what > > you do for module load/unload, except maybe less complete in some cases. > > I don't doubt your basic assessment. However it doesn't translate that > easily into a real implementation. In my case, I maintain a USB driver, > so I have to deal with USB specifics of suspend/resume which happen not > to be that well documented. My driver provides an isdn4linux device but > isdn4linux knows nothing about suspend/resume so I am on my own on how > to reconcile the two. The device itself, though in turn far from trivial, > is actually the least of my worries. > > >> - What if I know my device would require power management, but don't > >> know how to implement it? > > > > I've just told you above :) Now you know! > > No I don't. See above. > > >>> -ENOSYS is just not acceptable. > >> Your argument falls down the moment you consider the alternative: > >> not merging the driver means that the device won't work at all. > >> (Given that out-of-tree drivers are actively discouraged, to put > >> it mildly.) That's arguably farther from "desktop readiness" than > >> a device not supporting power management. > > > > I disagree (but I would, of course!). If we apply your logic > > consistently, we should merge the driver as soon as any code is written > > for it (anything is better than nothing). I'm simply arguing that a > > driver that handling suspend and resume should be as much of a > > requirement as not causing memory corruption or such like are. > > Well, that's a common fallacy about applying any logic consistently. > There's a continuum of usefulness from "hardly works at all" through > "causes random memory corruption", "doesn't support power management", > and "does not support some esoteric protocol variety no one ever heard > of anyways" up to "supports any and all uses to which anyone could > possibly want to put the device". I would argue that "doesn't support > power management" is *much* farther up that ladder than, for example, > "causes random memory corruption". I agree with that. Moreover, I think that the suspend/resume support is something you _can_ _live_ without while living, for instance, without networking at all would be difficult these days. Therefore I would certainly accept the driver that didn't support suspend/resume for my network adapter and I'd be happy to use it anyway. On the other hand, it would be nice if that driver did something that would prevent the system from suspending when it's loaded, just in case. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 0:10 ` Tilman Schmidt 2007-02-12 0:20 ` Rafael J. Wysocki @ 2007-02-12 4:08 ` Nigel Cunningham 2007-02-12 20:06 ` Rafael J. Wysocki 2007-03-03 22:48 ` Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) Tilman Schmidt 2 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-12 4:08 UTC (permalink / raw) To: Tilman Schmidt; +Cc: Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML Howdy! On Mon, 2007-02-12 at 01:10 +0100, Tilman Schmidt wrote: > Hi, > > Am 11.02.2007 23:37 schrieb Nigel Cunningham: > > On Sun, 2007-02-11 at 00:45 +0100, Tilman Schmidt wrote: > >> Am 10.02.2007 23:37 schrieb Nigel Cunningham: > >>> If your device requires power management, and you know it requires power > >>> management, why not just implement power management? [...] > >> Like it or not, power management is far from trivial, and people > >> writing device drivers have limited resources. [...] > > It's not that complex. All we're really talking about is a bit of extra > > code to cleanup and configure hardware state; things that the driver > > author already knows how to do. S3 might require a bit more > > initialisation if firmware needs to be reloaded or more extensive > > configuration needs to be done, but if there's firmware to be loaded, > > there is a reasonably good probability that we loaded it from Linux to > > start with anyway. > > You are assuming a perfect world where driver authors have complete > knowledge of their devices. In reality, many drivers (including > those I have the mixed pleasure of maintaining) are based at least > in part on reverse engineering, and managing power states may well > fall into the domain of things not yet sufficiently reverse > engineered. Nope. I'm assuming that the driver author knows what needs to be done to get the driver out of whatever state the BIOS puts it in to start with, and into an operational state, and that they therefore also know what needs to be done to take it out of the operational state again. I'm admitting that there's also another state - the post suspend-to-ram driver state - that they may not know how to deal with. But for suspend-to-disk, if you know how to get the driver to work in the first place, you know enough to stop it working (.suspend) and start it up again (.resume) for the hibernate case at least. I'm not assuming that you know enough to be able to put the driver into a low state and get it out again. This is definitely preferable, and at least possibly essential for suspend to ram, but for some unknown reason I'm quite hibernation focused, and for that, just the above is sufficient. > >> Also, in your argument you neglected a few cases: > >> - What if my device does not require power management? > > > > Then you as a generic routine that does nothing but return success > > (potentially shared with other drivers that are in the same situation). > > But if I just write an empty routine like that I open myself up to > criticism along the lines of "writing dummy routines just in order > to shut up kernel warnings". BTDT. Well, it might not be completely empty. I think someone already pointed out that there's a minimal workset for the pci bus that pci drivers would want to invoke. But we wouldn't (rightly) accuse you of such things if we decided that the policy was "Every driver ought to have a resume routine, even if it's just a minimal I-just-work route". > >> - What if I don't know whether my device requires power management? > > > > The questions are straight forward: Is there hardware state that needs > > to be configured if you've just booted the computer and nothing else has > > touched it? If so, that needs to be done in a resume method. Do you need > > to clean up state prior to doing the things in the resume method, or > > otherwise do things to quiesce the driver? If so, they will need to be > > done in the suspend method. The result will be roughly similar to what > > you do for module load/unload, except maybe less complete in some cases. > > I don't doubt your basic assessment. However it doesn't translate that > easily into a real implementation. In my case, I maintain a USB driver, > so I have to deal with USB specifics of suspend/resume which happen not > to be that well documented. My driver provides an isdn4linux device but > isdn4linux knows nothing about suspend/resume so I am on my own on how > to reconcile the two. The device itself, though in turn far from trivial, > is actually the least of my worries. Mmm, so that's a case where we need to prod those who write documentation and bus support first. You're probably closer! :) Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 4:08 ` Nigel Cunningham @ 2007-02-12 20:06 ` Rafael J. Wysocki 2007-02-12 22:38 ` Nigel Cunningham 0 siblings, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 20:06 UTC (permalink / raw) To: nigel; +Cc: Tilman Schmidt, Pavel Machek, Arjan van de Ven, LKML On Monday, 12 February 2007 05:08, Nigel Cunningham wrote: > Howdy! > > On Mon, 2007-02-12 at 01:10 +0100, Tilman Schmidt wrote: > > Hi, > > > > Am 11.02.2007 23:37 schrieb Nigel Cunningham: > > > On Sun, 2007-02-11 at 00:45 +0100, Tilman Schmidt wrote: > > >> Am 10.02.2007 23:37 schrieb Nigel Cunningham: > > >>> If your device requires power management, and you know it requires power > > >>> management, why not just implement power management? [...] > > >> Like it or not, power management is far from trivial, and people > > >> writing device drivers have limited resources. [...] > > > It's not that complex. All we're really talking about is a bit of extra > > > code to cleanup and configure hardware state; things that the driver > > > author already knows how to do. S3 might require a bit more > > > initialisation if firmware needs to be reloaded or more extensive > > > configuration needs to be done, but if there's firmware to be loaded, > > > there is a reasonably good probability that we loaded it from Linux to > > > start with anyway. > > > > You are assuming a perfect world where driver authors have complete > > knowledge of their devices. In reality, many drivers (including > > those I have the mixed pleasure of maintaining) are based at least > > in part on reverse engineering, and managing power states may well > > fall into the domain of things not yet sufficiently reverse > > engineered. > > Nope. I'm assuming that the driver author knows what needs to be done to > get the driver out of whatever state the BIOS puts it in to start with, > and into an operational state, and that they therefore also know what > needs to be done to take it out of the operational state again. I'm > admitting that there's also another state - the post suspend-to-ram > driver state - that they may not know how to deal with. But for > suspend-to-disk, if you know how to get the driver to work in the first > place, you know enough to stop it working (.suspend) and start it up > again (.resume) for the hibernate case at least. We're talking about _both_ the STR and STD. The drivers that have problems with the STR cannot be regarded as suspend/resume-safe IMO. > I'm not assuming that you know enough to be able to put the driver into > a low state and get it out again. This is definitely preferable, and at > least possibly essential for suspend to ram, but for some unknown reason > I'm quite hibernation focused, and for that, just the above is > sufficient. Please take the STR into consideration too. After all we use the same suspend/resume code for both STD and STR so it should work with both. If it doesn't work with one of them, we have a problem. > > >> Also, in your argument you neglected a few cases: > > >> - What if my device does not require power management? > > > > > > Then you as a generic routine that does nothing but return success > > > (potentially shared with other drivers that are in the same situation). > > > > But if I just write an empty routine like that I open myself up to > > criticism along the lines of "writing dummy routines just in order > > to shut up kernel warnings". BTDT. > > Well, it might not be completely empty. I think someone already pointed > out that there's a minimal workset for the pci bus that pci drivers > would want to invoke. But we wouldn't (rightly) accuse you of such > things if we decided that the policy was "Every driver ought to have a > resume routine, even if it's just a minimal I-just-work route". I'm still thinking that would be wasteful. I think there are more drivers that work than there are drivers that don't work. > > >> - What if I don't know whether my device requires power management? > > > > > > The questions are straight forward: Is there hardware state that needs > > > to be configured if you've just booted the computer and nothing else has > > > touched it? If so, that needs to be done in a resume method. Do you need > > > to clean up state prior to doing the things in the resume method, or > > > otherwise do things to quiesce the driver? If so, they will need to be > > > done in the suspend method. The result will be roughly similar to what > > > you do for module load/unload, except maybe less complete in some cases. > > > > I don't doubt your basic assessment. However it doesn't translate that > > easily into a real implementation. In my case, I maintain a USB driver, > > so I have to deal with USB specifics of suspend/resume which happen not > > to be that well documented. My driver provides an isdn4linux device but > > isdn4linux knows nothing about suspend/resume so I am on my own on how > > to reconcile the two. The device itself, though in turn far from trivial, > > is actually the least of my worries. > > Mmm, so that's a case where we need to prod those who write > documentation and bus support first. You're probably closer! :) Actually, the lack of documentation is a major problem that we all should try to fix in the first place. Unfortunately the code has been recently changing quite often, so that's difficult. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 20:06 ` Rafael J. Wysocki @ 2007-02-12 22:38 ` Nigel Cunningham 0 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-12 22:38 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Tilman Schmidt, Pavel Machek, Arjan van de Ven, LKML Hi. On Mon, 2007-02-12 at 21:06 +0100, Rafael J. Wysocki wrote: > On Monday, 12 February 2007 05:08, Nigel Cunningham wrote: > > Nope. I'm assuming that the driver author knows what needs to be done to > > get the driver out of whatever state the BIOS puts it in to start with, > > and into an operational state, and that they therefore also know what > > needs to be done to take it out of the operational state again. I'm > > admitting that there's also another state - the post suspend-to-ram > > driver state - that they may not know how to deal with. But for > > suspend-to-disk, if you know how to get the driver to work in the first > > place, you know enough to stop it working (.suspend) and start it up > > again (.resume) for the hibernate case at least. > > We're talking about _both_ the STR and STD. The drivers that have problems > with the STR cannot be regarded as suspend/resume-safe IMO. Yeah, I'm not disagreeing at all. I'm just admitting my bias toward the bit I concentrate on more. [...] > > Mmm, so that's a case where we need to prod those who write > > documentation and bus support first. You're probably closer! :) > > Actually, the lack of documentation is a major problem that we all should > try to fix in the first place. Unfortunately the code has been recently > changing quite often, so that's difficult. Yeah. Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) 2007-02-12 0:10 ` Tilman Schmidt 2007-02-12 0:20 ` Rafael J. Wysocki 2007-02-12 4:08 ` Nigel Cunningham @ 2007-03-03 22:48 ` Tilman Schmidt 2007-03-04 19:04 ` Rafael J. Wysocki 2 siblings, 1 reply; 77+ messages in thread From: Tilman Schmidt @ 2007-03-03 22:48 UTC (permalink / raw) To: LKML; +Cc: nigel, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven [-- Attachment #1: Type: text/plain, Size: 1207 bytes --] Ok, I've thought some more but I still don't know ... On 12.02.2007 01:10 I wrote: > I don't doubt your basic assessment. However it doesn't translate that > easily into a real implementation. In my case, I maintain a USB driver, > so I have to deal with USB specifics of suspend/resume which happen not > to be that well documented. My driver provides an isdn4linux device but > isdn4linux knows nothing about suspend/resume so I am on my own on how > to reconcile the two. The device itself, though in turn far from trivial, > is actually the least of my worries. So, how *should* an isdn4linux driver handle a request to suspend? Specifically, if there are active connections, should it try to shut them down in an orderly fashion (which might imply some delays waiting for the remote station to acknowledge, etc.)? Should it kill them abruptly (as for a USB unplug event)? Or should it just refuse to suspend while a connection is still active? Thanks for any insights, Tilman -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite) [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 253 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) 2007-03-03 22:48 ` Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) Tilman Schmidt @ 2007-03-04 19:04 ` Rafael J. Wysocki 2007-03-08 23:35 ` Pavel Machek 0 siblings, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-03-04 19:04 UTC (permalink / raw) To: Tilman Schmidt; +Cc: LKML, nigel, Pavel Machek, Arjan van de Ven On Saturday, 3 March 2007 23:48, Tilman Schmidt wrote: > Ok, I've thought some more but I still don't know ... > > On 12.02.2007 01:10 I wrote: > > I don't doubt your basic assessment. However it doesn't translate that > > easily into a real implementation. In my case, I maintain a USB driver, > > so I have to deal with USB specifics of suspend/resume which happen not > > to be that well documented. My driver provides an isdn4linux device but > > isdn4linux knows nothing about suspend/resume so I am on my own on how > > to reconcile the two. The device itself, though in turn far from trivial, > > is actually the least of my worries. > > So, how *should* an isdn4linux driver handle a request to suspend? > Specifically, if there are active connections, should it try to > shut them down in an orderly fashion (which might imply some delays > waiting for the remote station to acknowledge, etc.)? Should it kill > them abruptly (as for a USB unplug event)? Or should it just refuse > to suspend while a connection is still active? I think that refusing to suspend wouldn't be a good approach (think of an emergency suspend when the battery is running low). Probably the closing of connections would be the nicest thing from the user's point of view. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) 2007-03-04 19:04 ` Rafael J. Wysocki @ 2007-03-08 23:35 ` Pavel Machek 0 siblings, 0 replies; 77+ messages in thread From: Pavel Machek @ 2007-03-08 23:35 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Tilman Schmidt, LKML, nigel, Arjan van de Ven Hi! > > On 12.02.2007 01:10 I wrote: > > > I don't doubt your basic assessment. However it doesn't translate that > > > easily into a real implementation. In my case, I maintain a USB driver, > > > so I have to deal with USB specifics of suspend/resume which happen not > > > to be that well documented. My driver provides an isdn4linux device but > > > isdn4linux knows nothing about suspend/resume so I am on my own on how > > > to reconcile the two. The device itself, though in turn far from trivial, > > > is actually the least of my worries. > > > > So, how *should* an isdn4linux driver handle a request to suspend? > > Specifically, if there are active connections, should it try to > > shut them down in an orderly fashion (which might imply some delays > > waiting for the remote station to acknowledge, etc.)? Should it kill > > them abruptly (as for a USB unplug event)? Or should it just refuse > > to suspend while a connection is still active? > > I think that refusing to suspend wouldn't be a good approach (think of an > emergency suspend when the battery is running low). > > Probably the closing of connections would be the nicest thing from the > user's point of view. It depends on "how long does connection close take". If it is more than few seconds, kill them abruptly. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 22:37 ` Nigel Cunningham 2007-02-10 23:45 ` Tilman Schmidt @ 2007-02-11 6:46 ` Willy Tarreau 2007-02-11 13:04 ` Rafael J. Wysocki ` (3 more replies) 1 sibling, 4 replies; 77+ messages in thread From: Willy Tarreau @ 2007-02-11 6:46 UTC (permalink / raw) To: Nigel Cunningham Cc: Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman Hi Nigel, On Sun, Feb 11, 2007 at 09:37:06AM +1100, Nigel Cunningham wrote: > On Sat, 2007-02-10 at 23:20 +0100, Rafael J. Wysocki wrote: (...) > > What about this: > > > > "If the device requires that, implement .suspend and .resume or at least > > define .suspend that will always return -ENOSYS (then people will know they > > have to unload the driver before the suspend). Similarly, if you aren't sure > > whether or not the device requires .suspend and .resume, define .suspend that > > will always return -ENOSYS." > > If your device requires power management, and you know it requires power > management, why not just implement power management? Doing -ENOSYS > instead is like saying -ESPAMMEBECAUSEIMLAZY. No, it means "Not implemented because I don't want to screw that driver with something I'm not expert in". And it also means "Other people will quickly notice it and will know how to fix this if they really need it". > Let me put it another way: People keep talking about Linux being ready > for the desktop. To me at least (but I dare say for lots of other people > too), being ready for the desktop means that things just work, without > having to recompile kernels or bug driver authors or wait twelve > months. It's *one* usage of Linux. For this usage, you could also suggest to stop supporting UP kernels and always build everything with SMP enabled since more and more often, people will use multi-core systems. It will exempt the users from upgrading their kernels when they replace their CPU. We could also try to chase down all the drivers which do not correctly behave when the CPU switches to a lower frequency. > And it means that doing a bare minimum isn't enough. We keep claiming > that Open Source is better than Proprietary software. If we accept > half-pie jobs of implementing support for anything - driver power > management support or hibernation support or whatever - as 'good > enough', we're undercutting that argument. Linux's power management > support should - as far as we're able - be at least as good as that > other operating system's and preferably way, way better. > > -ENOSYS is just not acceptable. Nigel, don't take it as a personal offense, but I think it is a very centric view of Linux usages. Where I work, Linux is used a lot on servers and appliances. It is used for mail relays, HTTP proxies, anti-viruses, firewalls, routers, load balancers, UTM, SSH relays, etc... Nobody would ever want to enable power management on those machines, let alone suspend which would cause a major havoc, would the system decide to enter suspend for any reason. Many people also have Linux on their notebooks, but as a dual-boot. You read the word ? "dual-boot". It means that they cleanly shutdown their system every time they don't use it anymore, and they won't know what OS they'll use next time. I've never heard anyone there complaining "oh, I'm fed up with this boring boot, I always have to wait 30 seconds when I need to do something, I wish I could suspend and resume". It is considered the normal way of using their PCs. So globally, those hundreds of notebooks, workstations and servers will not be customers of the suspend code any time soon. It would be a shame to deprive them from working drivers. You must just accept that a lot of people are not interested in your work. It's the same for all of us here. I know that a lot of people are not interested in 2.4 anymore and I'm perfectly fine with that. I'm not asking 2.6 driver authors to ensure that their driver is easy to backport for instance. What I really think would be a clean solution would be sort of a capability. Either the driver *is* suspend/resume-capable, and the system can be suspended. Or it is not, and the system must refuse to suspend. It should not be a problem to proceed like this because drivers which will not support suspend will mainly be those which will not have to. And if a user occasionnaly complains that one driver does not support it, at least you will have a good argument against its author to implement suspend. Best regards, Willy ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau @ 2007-02-11 13:04 ` Rafael J. Wysocki 2007-02-11 22:47 ` Nigel Cunningham ` (2 subsequent siblings) 3 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-11 13:04 UTC (permalink / raw) To: Willy Tarreau Cc: Nigel Cunningham, Pavel Machek, Arjan van de Ven, LKML, tilman On Sunday, 11 February 2007 07:46, Willy Tarreau wrote: [--snip--] > What I really think would be a clean solution would be sort of > a capability. Either the driver *is* suspend/resume-capable, and > the system can be suspended. Or it is not, and the system must > refuse to suspend. It should not be a problem to proceed like > this because drivers which will not support suspend will mainly > be those which will not have to. And if a user occasionnaly > complains that one driver does not support it, at least you will > have a good argument against its author to implement suspend. I agree, but the suspend/resume safeness has to be somehow indicated by the driver. We could add a flag for that, but it would require us to modify lots of existing drivers (unless there's something obvious I don't see). However, the driver can effectively say "I'm not suspend/resume-safe" by returning an error from .suspend(), in which case the system will automatically refuse to suspend. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau 2007-02-11 13:04 ` Rafael J. Wysocki @ 2007-02-11 22:47 ` Nigel Cunningham 2007-02-11 22:57 ` Manu Abraham 2007-02-12 12:59 ` Gerhard Mack 2007-02-12 13:51 ` Tino Keitel 3 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 22:47 UTC (permalink / raw) To: Willy Tarreau Cc: Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman Hi. On Sun, 2007-02-11 at 07:46 +0100, Willy Tarreau wrote: > Hi Nigel, > > On Sun, Feb 11, 2007 at 09:37:06AM +1100, Nigel Cunningham wrote: > > On Sat, 2007-02-10 at 23:20 +0100, Rafael J. Wysocki wrote: > (...) > > > What about this: > > > > > > "If the device requires that, implement .suspend and .resume or at least > > > define .suspend that will always return -ENOSYS (then people will know they > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > whether or not the device requires .suspend and .resume, define .suspend that > > > will always return -ENOSYS." > > > > If your device requires power management, and you know it requires power > > management, why not just implement power management? Doing -ENOSYS > > instead is like saying -ESPAMMEBECAUSEIMLAZY. > > No, it means "Not implemented because I don't want to screw that driver with > something I'm not expert in". And it also means "Other people will quickly > notice it and will know how to fix this if they really need it". Ok, that was a bit rough. Sorry. At the same time though, we were talking about new drivers. If you know enough to implement the rest of the driver, surely you know enough to implement the power management part too. (See my previous comment about the similarities to module load/unload code). > > Let me put it another way: People keep talking about Linux being ready > > for the desktop. To me at least (but I dare say for lots of other people > > too), being ready for the desktop means that things just work, without > > having to recompile kernels or bug driver authors or wait twelve > > months. > > It's *one* usage of Linux. For this usage, you could also suggest to stop > supporting UP kernels and always build everything with SMP enabled since > more and more often, people will use multi-core systems. It will exempt > the users from upgrading their kernels when they replace their CPU. We > could also try to chase down all the drivers which do not correctly behave > when the CPU switches to a lower frequency. > > > And it means that doing a bare minimum isn't enough. We keep claiming > > that Open Source is better than Proprietary software. If we accept > > half-pie jobs of implementing support for anything - driver power > > management support or hibernation support or whatever - as 'good > > enough', we're undercutting that argument. Linux's power management > > support should - as far as we're able - be at least as good as that > > other operating system's and preferably way, way better. > > > > -ENOSYS is just not acceptable. > > Nigel, don't take it as a personal offense, but I think it is a very > centric view of Linux usages. Where I work, Linux is used a lot on > servers and appliances. It is used for mail relays, HTTP proxies, > anti-viruses, firewalls, routers, load balancers, UTM, SSH relays, > etc... Nobody would ever want to enable power management on those > machines, let alone suspend which would cause a major havoc, would > the system decide to enter suspend for any reason. I agree. > Many people also have Linux on their notebooks, but as a dual-boot. You > read the word ? "dual-boot". It means that they cleanly shutdown their > system every time they don't use it anymore, and they won't know what > OS they'll use next time. Not necessarily. I dual boot our desktop machine, and hibernate both, using grub to select with OS to run. > I've never heard anyone there complaining "oh, I'm fed up with this > boring boot, I always have to wait 30 seconds when I need to do > something, I wish I could suspend and resume". It is considered the > normal way of using their PCs. > > So globally, those hundreds of notebooks, workstations and servers > will not be customers of the suspend code any time soon. It would > be a shame to deprive them from working drivers. You must just > accept that a lot of people are not interested in your work. It's > the same for all of us here. I know that a lot of people are not > interested in 2.4 anymore and I'm perfectly fine with that. I'm > not asking 2.6 driver authors to ensure that their driver is easy > to backport for instance. Neither am I. I'm just asking that new drivers have power management as standard. > What I really think would be a clean solution would be sort of > a capability. Either the driver *is* suspend/resume-capable, and > the system can be suspended. Or it is not, and the system must > refuse to suspend. It should not be a problem to proceed like > this because drivers which will not support suspend will mainly > be those which will not have to. And if a user occasionnaly > complains that one driver does not support it, at least you will > have a good argument against its author to implement suspend. Yes, but why should the user have to complain to start with? Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 22:47 ` Nigel Cunningham @ 2007-02-11 22:57 ` Manu Abraham 2007-02-11 23:20 ` Nigel Cunningham 0 siblings, 1 reply; 77+ messages in thread From: Manu Abraham @ 2007-02-11 22:57 UTC (permalink / raw) To: nigel Cc: Willy Tarreau, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman On 2/12/07, Nigel Cunningham <nigel@nigel.suspend2.net> wrote: > Neither am I. I'm just asking that new drivers have power management as > standard. What if the hardware doesn't support power management ? regards, manu ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 22:57 ` Manu Abraham @ 2007-02-11 23:20 ` Nigel Cunningham 2007-02-11 23:25 ` Manu Abraham 0 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 23:20 UTC (permalink / raw) To: Manu Abraham Cc: Willy Tarreau, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman Hi. On Mon, 2007-02-12 at 02:57 +0400, Manu Abraham wrote: > On 2/12/07, Nigel Cunningham <nigel@nigel.suspend2.net> wrote: > > > Neither am I. I'm just asking that new drivers have power management as > > standard. > What if the hardware doesn't support power management ? You would still want to do the cleanup and configuration that you'd do for module load/unload. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:20 ` Nigel Cunningham @ 2007-02-11 23:25 ` Manu Abraham 2007-02-11 23:29 ` Pavel Machek ` (2 more replies) 0 siblings, 3 replies; 77+ messages in thread From: Manu Abraham @ 2007-02-11 23:25 UTC (permalink / raw) To: nigel Cc: Willy Tarreau, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman On 2/12/07, Nigel Cunningham <nigel@nigel.suspend2.net> wrote: > Hi. > > On Mon, 2007-02-12 at 02:57 +0400, Manu Abraham wrote: > > On 2/12/07, Nigel Cunningham <nigel@nigel.suspend2.net> wrote: > > > > > Neither am I. I'm just asking that new drivers have power management as > > > standard. > > > What if the hardware doesn't support power management ? > > You would still want to do the cleanup and configuration that you'd do > for module load/unload. > By adding dummy functions, wouldn't that just look awkward ? regards, manu ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:25 ` Manu Abraham @ 2007-02-11 23:29 ` Pavel Machek 2007-02-11 23:33 ` Nigel Cunningham 2007-02-12 9:45 ` Arjan van de Ven 2 siblings, 0 replies; 77+ messages in thread From: Pavel Machek @ 2007-02-11 23:29 UTC (permalink / raw) To: Manu Abraham Cc: nigel, Willy Tarreau, Rafael J. Wysocki, Arjan van de Ven, LKML, tilman Hi! > >> > Neither am I. I'm just asking that new drivers have power management as > >> > standard. > > > >> What if the hardware doesn't support power management ? > > > >You would still want to do the cleanup and configuration that you'd do > >for module load/unload. > > > > By adding dummy functions, wouldn't that just look awkward ? No, it is not by dummy functions. Checkout how swsusp works; it needs no hw support, still it needs driver support. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:25 ` Manu Abraham 2007-02-11 23:29 ` Pavel Machek @ 2007-02-11 23:33 ` Nigel Cunningham 2007-02-12 16:52 ` Pavel Machek 2007-02-12 9:45 ` Arjan van de Ven 2 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 23:33 UTC (permalink / raw) To: Manu Abraham Cc: Willy Tarreau, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman Hi. On Mon, 2007-02-12 at 03:25 +0400, Manu Abraham wrote: > On 2/12/07, Nigel Cunningham <nigel@nigel.suspend2.net> wrote: > > Hi. > > > > On Mon, 2007-02-12 at 02:57 +0400, Manu Abraham wrote: > > > On 2/12/07, Nigel Cunningham <nigel@nigel.suspend2.net> wrote: > > > > > > > Neither am I. I'm just asking that new drivers have power management as > > > > standard. > > > > > What if the hardware doesn't support power management ? > > > > You would still want to do the cleanup and configuration that you'd do > > for module load/unload. > > > By adding dummy functions, wouldn't that just look awkward ? If all you need to do is say 'I don't need to do anything' and we have a shared function that does that, all we're talking about doing is adding to your struct pci_device (or whatever) .resume = generic_empty_resume; To me at least, that doesn't look awkward, and says cleanly and clearly that you've checked things over and decided you know what's required. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:33 ` Nigel Cunningham @ 2007-02-12 16:52 ` Pavel Machek 2007-02-12 20:31 ` Rafael J. Wysocki 0 siblings, 1 reply; 77+ messages in thread From: Pavel Machek @ 2007-02-12 16:52 UTC (permalink / raw) To: Nigel Cunningham Cc: Manu Abraham, Willy Tarreau, Rafael J. Wysocki, Arjan van de Ven, LKML, tilman Hi! > > > > > Neither am I. I'm just asking that new drivers have power management as > > > > > standard. > > > > > > > What if the hardware doesn't support power management ? > > > > > > You would still want to do the cleanup and configuration that you'd do > > > for module load/unload. > > > > > By adding dummy functions, wouldn't that just look awkward ? > > If all you need to do is say 'I don't need to do anything' and we have a > shared function that does that, all we're talking about doing is adding > to your struct pci_device (or whatever) > > .resume = generic_empty_resume; > > To me at least, that doesn't look awkward, and says cleanly and clearly > that you've checked things over and decided you know what's required. Actually, I'd like it to be .resume = generic_empty_resume; /* Explain, why your driver needs no resume */ -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 16:52 ` Pavel Machek @ 2007-02-12 20:31 ` Rafael J. Wysocki 2007-02-12 20:58 ` Pavel Machek 2007-02-13 9:42 ` Tilman Schmidt 0 siblings, 2 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 20:31 UTC (permalink / raw) To: Pavel Machek Cc: Nigel Cunningham, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, tilman, Robert Hancock On Monday, 12 February 2007 17:52, Pavel Machek wrote: > Hi! > > > > > > > Neither am I. I'm just asking that new drivers have power management as > > > > > > standard. > > > > > > > > > What if the hardware doesn't support power management ? > > > > > > > > You would still want to do the cleanup and configuration that you'd do > > > > for module load/unload. > > > > > > > By adding dummy functions, wouldn't that just look awkward ? > > > > If all you need to do is say 'I don't need to do anything' and we have a > > shared function that does that, all we're talking about doing is adding > > to your struct pci_device (or whatever) > > > > .resume = generic_empty_resume; > > > > To me at least, that doesn't look awkward, and says cleanly and clearly > > that you've checked things over and decided you know what's required. > > Actually, I'd like it to be > > .resume = generic_empty_resume; /* Explain, why your driver needs no > resume */ Okay, but we can't define an empty .resume(), because, for example, the PCI's generic suspend/resume won't be called. I think we can introduce a "pm_safe" flag that will indicate if the driver handles suspend/resume correctly. If we do it, we can flag all of the drivers currently in the tree as "pm_safe" unless we know that they aren't. Next, we can convert the core to fail the suspend for any driver that is not flagged as "pm_safe". But I think that will take time. In the meantime, I'd like to ask the authors of new drivers to define error-returning .suspend() if they don't intend to define "real" .suspend() and .resume() for now. When we are ready with the conversion, we'll be able to drop the error-returning .suspend()s and clear "pm_safe" for them. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 20:31 ` Rafael J. Wysocki @ 2007-02-12 20:58 ` Pavel Machek 2007-02-12 21:01 ` Rafael J. Wysocki 2007-02-13 9:42 ` Tilman Schmidt 1 sibling, 1 reply; 77+ messages in thread From: Pavel Machek @ 2007-02-12 20:58 UTC (permalink / raw) To: Rafael J. Wysocki Cc: Nigel Cunningham, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, tilman, Robert Hancock Hi! > > > If all you need to do is say 'I don't need to do anything' and we have a > > > shared function that does that, all we're talking about doing is adding > > > to your struct pci_device (or whatever) > > > > > > .resume = generic_empty_resume; > > > > > > To me at least, that doesn't look awkward, and says cleanly and clearly > > > that you've checked things over and decided you know what's required. > > > > Actually, I'd like it to be > > > > .resume = generic_empty_resume; /* Explain, why your driver needs no > > resume */ > > Okay, but we can't define an empty .resume(), because, for example, the PCI's > generic suspend/resume won't be called. PCI drivers should just do .resume = pci_generic_resume, explicitely. > In the meantime, I'd like to ask the authors of new drivers to define > error-returning .suspend() if they don't intend to define "real" .suspend() > and .resume() for now. When we are ready with the conversion, we'll be able > to drop the error-returning .suspend()s and clear "pm_safe" for them. Yes... please. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 20:58 ` Pavel Machek @ 2007-02-12 21:01 ` Rafael J. Wysocki 2007-02-12 21:24 ` Nigel Cunningham 0 siblings, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 21:01 UTC (permalink / raw) To: Pavel Machek Cc: Nigel Cunningham, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, tilman, Robert Hancock On Monday, 12 February 2007 21:58, Pavel Machek wrote: > Hi! > > > > > If all you need to do is say 'I don't need to do anything' and we have a > > > > shared function that does that, all we're talking about doing is adding > > > > to your struct pci_device (or whatever) > > > > > > > > .resume = generic_empty_resume; > > > > > > > > To me at least, that doesn't look awkward, and says cleanly and clearly > > > > that you've checked things over and decided you know what's required. > > > > > > Actually, I'd like it to be > > > > > > .resume = generic_empty_resume; /* Explain, why your driver needs no > > > resume */ > > > > Okay, but we can't define an empty .resume(), because, for example, the PCI's > > generic suspend/resume won't be called. > > PCI drivers should just do .resume = pci_generic_resume, explicitely. Well, I generally agree, but I think the idea with the "pm_safe" flag has some advantages. For example, the drivers that do deffine .suspend() and .resume() which don't work correctly could be flagged as not "pm_safe" until the problems are fixed. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 21:01 ` Rafael J. Wysocki @ 2007-02-12 21:24 ` Nigel Cunningham 2007-02-12 21:43 ` Rafael J. Wysocki 0 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-12 21:24 UTC (permalink / raw) To: Rafael J. Wysocki Cc: Pavel Machek, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, tilman, Robert Hancock Hi. On Mon, 2007-02-12 at 22:01 +0100, Rafael J. Wysocki wrote: > On Monday, 12 February 2007 21:58, Pavel Machek wrote: > > Hi! > > > > > > > If all you need to do is say 'I don't need to do anything' and we have a > > > > > shared function that does that, all we're talking about doing is adding > > > > > to your struct pci_device (or whatever) > > > > > > > > > > .resume = generic_empty_resume; > > > > > > > > > > To me at least, that doesn't look awkward, and says cleanly and clearly > > > > > that you've checked things over and decided you know what's required. > > > > > > > > Actually, I'd like it to be > > > > > > > > .resume = generic_empty_resume; /* Explain, why your driver needs no > > > > resume */ > > > > > > Okay, but we can't define an empty .resume(), because, for example, the PCI's > > > generic suspend/resume won't be called. > > > > PCI drivers should just do .resume = pci_generic_resume, explicitely. > > Well, I generally agree, but I think the idea with the "pm_safe" flag has some > advantages. For example, the drivers that do deffine .suspend() and .resume() > which don't work correctly could be flagged as not "pm_safe" until the problems > are fixed. Oooh. Now I like that idea. Are you thinking of a document in Documentation/power that describes why pm_safe is off, or comments in the code itself? Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 21:24 ` Nigel Cunningham @ 2007-02-12 21:43 ` Rafael J. Wysocki 0 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 21:43 UTC (permalink / raw) To: nigel Cc: Pavel Machek, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, tilman, Robert Hancock On Monday, 12 February 2007 22:24, Nigel Cunningham wrote: > Hi. > > On Mon, 2007-02-12 at 22:01 +0100, Rafael J. Wysocki wrote: > > On Monday, 12 February 2007 21:58, Pavel Machek wrote: > > > Hi! > > > > > > > > > If all you need to do is say 'I don't need to do anything' and we have a > > > > > > shared function that does that, all we're talking about doing is adding > > > > > > to your struct pci_device (or whatever) > > > > > > > > > > > > .resume = generic_empty_resume; > > > > > > > > > > > > To me at least, that doesn't look awkward, and says cleanly and clearly > > > > > > that you've checked things over and decided you know what's required. > > > > > > > > > > Actually, I'd like it to be > > > > > > > > > > .resume = generic_empty_resume; /* Explain, why your driver needs no > > > > > resume */ > > > > > > > > Okay, but we can't define an empty .resume(), because, for example, the PCI's > > > > generic suspend/resume won't be called. > > > > > > PCI drivers should just do .resume = pci_generic_resume, explicitely. > > > > Well, I generally agree, but I think the idea with the "pm_safe" flag has some > > advantages. For example, the drivers that do define .suspend() and .resume() > > which don't work correctly could be flagged as not "pm_safe" until the problems > > are fixed. > > Oooh. Now I like that idea. Are you thinking of a document in > Documentation/power that describes why pm_safe is off, or comments in > the code itself? I think the code should be commented in the first place. Additionally, we can create a file or a directory under Documentation/power for documenting more complicated cases, if necessary. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 20:31 ` Rafael J. Wysocki 2007-02-12 20:58 ` Pavel Machek @ 2007-02-13 9:42 ` Tilman Schmidt 2007-02-13 19:24 ` Rafael J. Wysocki 1 sibling, 1 reply; 77+ messages in thread From: Tilman Schmidt @ 2007-02-13 9:42 UTC (permalink / raw) To: Rafael J. Wysocki Cc: Pavel Machek, Nigel Cunningham, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, tilman, Robert Hancock [-- Attachment #1: Type: text/plain, Size: 1440 bytes --] Rafael J. Wysocki schrieb: > I think we can introduce a "pm_safe" flag that will indicate if the driver > handles suspend/resume correctly. If we do it, we can flag all of the drivers > currently in the tree as "pm_safe" unless we know that they aren't. Next, > we can convert the core to fail the suspend for any driver that is not flagged > as "pm_safe". But I think that will take time. Why a new flag? IMHO it would be both more readable and more efficient to create a pm_generic_nosuspend() function which does "return -ENOSYS", and set that as the .suspend method on drivers known to break suspend/resume. New drivers should either have .suspend and .resume methods of their own or set .suspend = pm_generic_nosuspend. That way, NULL .suspend/.resume methods retain their current semantics ("don't know whether suspend would work, never thought about it"), error-returning ones would clearly signal "cannot suspend safely", and success-returning ones would equally clearly signal "suspend works ok". (Bugs nonwithstanding.) There could then be a policy parameter (Kconfig selectable to start) to abort suspend when encountering a driver without .suspend/.resume methods, or to proceed with a warning message. -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite) [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 250 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-13 9:42 ` Tilman Schmidt @ 2007-02-13 19:24 ` Rafael J. Wysocki 2007-02-14 23:45 ` Stefan Richter 0 siblings, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-13 19:24 UTC (permalink / raw) To: Tilman Schmidt Cc: Pavel Machek, Nigel Cunningham, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, Robert Hancock On Tuesday, 13 February 2007 10:42, Tilman Schmidt wrote: > Rafael J. Wysocki schrieb: > > I think we can introduce a "pm_safe" flag that will indicate if the driver > > handles suspend/resume correctly. If we do it, we can flag all of the drivers > > currently in the tree as "pm_safe" unless we know that they aren't. Next, > > we can convert the core to fail the suspend for any driver that is not flagged > > as "pm_safe". But I think that will take time. > > Why a new flag? For example, there are drivers that define .suspend() and .resume() which do not work correctly and we can use the flag to mark them. > IMHO it would be both more readable and more efficient > to create a pm_generic_nosuspend() function which does "return -ENOSYS", > and set that as the .suspend method on drivers known to break > suspend/resume. New drivers should either have .suspend and .resume > methods of their own or set .suspend = pm_generic_nosuspend. This is quite similar to what we are trying to do now: ask driver authors to define .suspend that will return -ENOSYS if they can't ensure that the driver will handle the suspend and resume correctly. > That way, NULL .suspend/.resume methods retain their current semantics > ("don't know whether suspend would work, never thought about it"), I think this convention is unfortunate. The default should be to fail the suspend if there's no .suspend defined, IMO. Still, it's hard to change now. > error-returning ones would clearly signal "cannot suspend safely", and > success-returning ones would equally clearly signal "suspend works ok". > (Bugs nonwithstanding.) > > There could then be a policy parameter (Kconfig selectable to start) > to abort suspend when encountering a driver without .suspend/.resume > methods, or to proceed with a warning message. I think there are many drivers without .suspend and .resume already in the tree, so that wouldn't be practical. Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-13 19:24 ` Rafael J. Wysocki @ 2007-02-14 23:45 ` Stefan Richter 0 siblings, 0 replies; 77+ messages in thread From: Stefan Richter @ 2007-02-14 23:45 UTC (permalink / raw) To: Rafael J. Wysocki Cc: Tilman Schmidt, Pavel Machek, Nigel Cunningham, Manu Abraham, Willy Tarreau, Arjan van de Ven, LKML, Robert Hancock Rafael J. Wysocki wrote: >> Why a new flag? > > For example, there are drivers that define .suspend() and .resume() which > do not work correctly and we can use the flag to mark them. Depending on how serious the problems with these .suspend/.resume()s are, you could also put a printk in them or #if 0 bad_code #else return -ENOSYS #endif around them. ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:25 ` Manu Abraham 2007-02-11 23:29 ` Pavel Machek 2007-02-11 23:33 ` Nigel Cunningham @ 2007-02-12 9:45 ` Arjan van de Ven 2 siblings, 0 replies; 77+ messages in thread From: Arjan van de Ven @ 2007-02-12 9:45 UTC (permalink / raw) To: Manu Abraham Cc: nigel, Willy Tarreau, Rafael J. Wysocki, Pavel Machek, LKML, tilman > > By adding dummy functions, wouldn't that just look awkward ? not really; if you have a template pm_no_suspend_needed and pm_no_restore_needed functions, and just make it part of ALL device structs that don't need it.. it's not that bad or maybe pm_generic_no_suspend pm_generic_no_resume as names, more in line what we use elsewhere in the kernel -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau 2007-02-11 13:04 ` Rafael J. Wysocki 2007-02-11 22:47 ` Nigel Cunningham @ 2007-02-12 12:59 ` Gerhard Mack 2007-02-12 20:20 ` Willy Tarreau 2007-02-12 20:46 ` Rafael J. Wysocki 2007-02-12 13:51 ` Tino Keitel 3 siblings, 2 replies; 77+ messages in thread From: Gerhard Mack @ 2007-02-12 12:59 UTC (permalink / raw) To: Willy Tarreau Cc: Nigel Cunningham, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman On Sun, 11 Feb 2007, Willy Tarreau wrote: > On Sun, Feb 11, 2007 at 09:37:06AM +1100, Nigel Cunningham wrote: > > On Sat, 2007-02-10 at 23:20 +0100, Rafael J. Wysocki wrote: > > Many people also have Linux on their notebooks, but as a dual-boot. You > read the word ? "dual-boot". It means that they cleanly shutdown their > system every time they don't use it anymore, and they won't know what > OS they'll use next time. Please tell me your joking. Linux' crappy suspend support is a common reason people give me for not wanting Linux anywhere near their laptops. I have a single boot laptop that's somewhat of a mobile debugging station that needs Linux and I absolutely hate it. Right now my laptop takes far too long to boot and even if it didn't I wish I could suspend. I'm actually a huge Linux fan.. I use it exclusively on my server and on my PC but if I get another laptop I will probably run something else on it. Linux is just too annoying for that use. Gerhard -- Gerhard Mack gmack@innerfire.net <>< As a computer I find your faith in technology amusing. ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 12:59 ` Gerhard Mack @ 2007-02-12 20:20 ` Willy Tarreau 2007-02-13 15:23 ` Brad Campbell 2007-02-12 20:46 ` Rafael J. Wysocki 1 sibling, 1 reply; 77+ messages in thread From: Willy Tarreau @ 2007-02-12 20:20 UTC (permalink / raw) To: Gerhard Mack Cc: Nigel Cunningham, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman On Mon, Feb 12, 2007 at 07:59:40AM -0500, Gerhard Mack wrote: > On Sun, 11 Feb 2007, Willy Tarreau wrote: > > > On Sun, Feb 11, 2007 at 09:37:06AM +1100, Nigel Cunningham wrote: > > > On Sat, 2007-02-10 at 23:20 +0100, Rafael J. Wysocki wrote: > > > > Many people also have Linux on their notebooks, but as a dual-boot. You > > read the word ? "dual-boot". It means that they cleanly shutdown their > > system every time they don't use it anymore, and they won't know what > > OS they'll use next time. > > Please tell me your joking. Linux' crappy suspend support is a common > reason people give me for not wanting Linux anywhere near their laptops. No, I'm not kidding. The most annoyed ones are those who don't have serial ports and who need those annoying USB adapters. But fortunately, not all of them need to access router consoles :-) > I have a single boot laptop that's somewhat of a mobile debugging station > that needs Linux and I absolutely hate it. Right now my laptop takes far > too long to boot and even if it didn't I wish I could suspend. Probably that you got the wrong laptop. If you buy an ultra-thin with highly proprietary hardware, it may be hard. But if you choose in profesionnal ranges, there is rarely any problem. I have a compaq nc8000 on which everything works fine, and it boots in about 20 seconds. Other people I know have Toshibas, NECs, Dells and IBMs and are happy with them. My previous VAIO was a dirty crap that I would never recommend to anybody though. > I'm actually a huge Linux fan.. I use it exclusively on my server and on > my PC but if I get another laptop I will probably run something else on > it. Linux is just too annoying for that use. Everyone has different needs, that's all. Sorry, but I fell like we're becoming a bit off-topic here. Regards, Willy ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 20:20 ` Willy Tarreau @ 2007-02-13 15:23 ` Brad Campbell 0 siblings, 0 replies; 77+ messages in thread From: Brad Campbell @ 2007-02-13 15:23 UTC (permalink / raw) To: Willy Tarreau Cc: Gerhard Mack, Nigel Cunningham, Rafael J. Wysocki, Pavel Machek, Arjan van de Ven, LKML, tilman Willy Tarreau wrote: > Probably that you got the wrong laptop. If you buy an ultra-thin with highly > proprietary hardware, it may be hard. But if you choose in profesionnal ranges, > there is rarely any problem. I have a compaq nc8000 on which everything works > fine, and it boots in about 20 seconds. Other people I know have Toshibas, > NECs, Dells and IBMs and are happy with them. My previous VAIO was a dirty > crap that I would never recommend to anybody though. Whereas my "ultru-thin" VAIO works perfectly with both S2D and S2R and the only thing I have some difficulty with is the SD reader. Would not hesitate to recommend it to anyone. I often hibernate linux to boot into a hibernated windows session, then go back the other way as required, and my machine might do 80-100 "suspend2both" sessions a month between reboots. 30-40 seconds to suspend mostly (1.5GB of RAM) and about 15 to come back. That's what I call highly useful. Different strokes and all that I guess.. Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 12:59 ` Gerhard Mack 2007-02-12 20:20 ` Willy Tarreau @ 2007-02-12 20:46 ` Rafael J. Wysocki 1 sibling, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 20:46 UTC (permalink / raw) To: Gerhard Mack Cc: Willy Tarreau, Nigel Cunningham, Pavel Machek, Arjan van de Ven, LKML, tilman On Monday, 12 February 2007 13:59, Gerhard Mack wrote: > On Sun, 11 Feb 2007, Willy Tarreau wrote: > > > On Sun, Feb 11, 2007 at 09:37:06AM +1100, Nigel Cunningham wrote: > > > On Sat, 2007-02-10 at 23:20 +0100, Rafael J. Wysocki wrote: > > > > Many people also have Linux on their notebooks, but as a dual-boot. You > > read the word ? "dual-boot". It means that they cleanly shutdown their > > system every time they don't use it anymore, and they won't know what > > OS they'll use next time. > > Please tell me your joking. Linux' crappy suspend support is a common > reason people give me for not wanting Linux anywhere near their laptops. > > I have a single boot laptop that's somewhat of a mobile debugging station > that needs Linux and I absolutely hate it. Right now my laptop takes far > too long to boot and even if it didn't I wish I could suspend. When did you try last time? Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau ` (2 preceding siblings ...) 2007-02-12 12:59 ` Gerhard Mack @ 2007-02-12 13:51 ` Tino Keitel 3 siblings, 0 replies; 77+ messages in thread From: Tino Keitel @ 2007-02-12 13:51 UTC (permalink / raw) To: LKML On Sun, Feb 11, 2007 at 07:46:36 +0100, Willy Tarreau wrote: [...] > Many people also have Linux on their notebooks, but as a dual-boot. You > read the word ? "dual-boot". It means that they cleanly shutdown their > system every time they don't use it anymore, and they won't know what > OS they'll use next time. I can suspend to disk my Mac mini, reboot into MacOS X, shutdown, and then resume in Linux. I also did this with APM suspend to disk support on my ThinkPad some years ago, using Linux and Windows. So, dualboot and suspend support isn't mutual exclusive. This is only the case if suspend is limited to suspend to RAM. Regards, Tino ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 22:20 ` Rafael J. Wysocki 2007-02-10 22:37 ` Nigel Cunningham @ 2007-02-11 19:42 ` Pavel Machek 2007-02-11 21:02 ` Alan 2007-02-11 22:21 ` Tilman Schmidt 2007-02-12 8:49 ` Geert Uytterhoeven 2 siblings, 2 replies; 77+ messages in thread From: Pavel Machek @ 2007-02-11 19:42 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Arjan van de Ven, nigel, LKML Hi! > > > > Can we start to NAK new drivers that don't have proper power management > > > > implemented? There really is no excuse for writing a new driver and not > > > > putting .suspend and .resume methods in anymore, is there? > > > > > > to a large degree, a device driver that doesn't suspend is better than > > > no device driver at all, right? > > > now.. if you want to make the core warn about it, that's very fair > > > > Well, driver that is broken on SMP is arguably better than no driver > > at all, yet we'd probably avoid merging that. It would be nice to > > start including suspend in 'must work' list... > > What about this: > > "If the device requires that, implement .suspend and .resume or at least > define .suspend that will always return -ENOSYS (then people will know they > have to unload the driver before the suspend). Similarly, if you aren't sure > whether or not the device requires .suspend and .resume, define .suspend that > will always return -ENOSYS." Sounds ok to me. Where should this text go? Documentation/SubmittingDrivers ? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 19:42 ` Pavel Machek @ 2007-02-11 21:02 ` Alan 2007-02-11 23:04 ` Rafael J. Wysocki 2007-02-11 23:10 ` Nigel Cunningham 2007-02-11 22:21 ` Tilman Schmidt 1 sibling, 2 replies; 77+ messages in thread From: Alan @ 2007-02-11 21:02 UTC (permalink / raw) To: Pavel Machek; +Cc: Rafael J. Wysocki, Arjan van de Ven, nigel, LKML > > "If the device requires that, implement .suspend and .resume or at least > > define .suspend that will always return -ENOSYS (then people will know they > > have to unload the driver before the suspend). Similarly, if you aren't sure > > whether or not the device requires .suspend and .resume, define .suspend that > > will always return -ENOSYS." > > Sounds ok to me. Where should this text go? > Documentation/SubmittingDrivers ? And testing/submitting drivers, perhaps with additional text in that to make it clear we want suspend/resume support or good excuses "Please verify your driver correctly handles suspend and resume. If it does not your patch submission is likely to be suspended and only resume when the driver correctly handles this feature" ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 21:02 ` Alan @ 2007-02-11 23:04 ` Rafael J. Wysocki 2007-02-12 0:28 ` Alan 2007-02-11 23:10 ` Nigel Cunningham 1 sibling, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-11 23:04 UTC (permalink / raw) To: Alan; +Cc: Pavel Machek, Arjan van de Ven, nigel, LKML On Sunday, 11 February 2007 22:02, Alan wrote: > > > "If the device requires that, implement .suspend and .resume or at least > > > define .suspend that will always return -ENOSYS (then people will know they > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > whether or not the device requires .suspend and .resume, define .suspend that > > > will always return -ENOSYS." > > > > Sounds ok to me. Where should this text go? > > Documentation/SubmittingDrivers ? > > And testing/submitting drivers, perhaps with additional text in that to > make it clear we want suspend/resume support or good excuses > > "Please verify your driver correctly handles suspend and resume. If it > does not your patch submission is likely to be suspended and only resume > when the driver correctly handles this feature" I have prepared a patch against Documentation/SubmittingDrivers. Please have a look. --- Documentation/SubmittingDrivers | 12 ++++++++++++ 1 file changed, 12 insertions(+) Index: linux-2.6.20-git4/Documentation/SubmittingDrivers =================================================================== --- linux-2.6.20-git4.orig/Documentation/SubmittingDrivers +++ linux-2.6.20-git4/Documentation/SubmittingDrivers @@ -87,6 +87,18 @@ Clarity: It helps if anyone can see how driver that intentionally obfuscates how the hardware works it will go in the bitbucket. +PM support: Since Linux is used on many portable and desktop systems, your + driver is likely to be used on such a system and therefore it + should support basic power management by implementing, if + necessary, the .suspend and .resume methods used during the + system-wide suspend and resume transitions. You should verify + that your driver correctly handles the suspend and resume, but + if you are unable to ensure that, please at least define the + .suspend method returning the -ENOSYS ("Function not + implemented") error. Note, however, that in such a case your + submission is likely to be suspended and only resumed when the + driver correctly handles this feature. + Control: In general if there is active maintainance of a driver by the author then patches will be redirected to them unless they are totally obvious and without need of checking. ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:04 ` Rafael J. Wysocki @ 2007-02-12 0:28 ` Alan 2007-02-12 0:24 ` Rafael J. Wysocki 0 siblings, 1 reply; 77+ messages in thread From: Alan @ 2007-02-12 0:28 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Pavel Machek, Arjan van de Ven, nigel, LKML > +PM support: Since Linux is used on many portable and desktop systems, your > + driver is likely to be used on such a system and therefore it > + should support basic power management by implementing, if > + necessary, the .suspend and .resume methods used during the > + system-wide suspend and resume transitions. You should verify > + that your driver correctly handles the suspend and resume, but > + if you are unable to ensure that, please at least define the > + .suspend method returning the -ENOSYS ("Function not > + implemented") error. Note, however, that in such a case your > + submission is likely to be suspended and only resumed when the > + driver correctly handles this feature. I'd lose the last bit. Just end it at "error.", there are going to be people who produce good reasons not to handle suspend/resume. ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 0:28 ` Alan @ 2007-02-12 0:24 ` Rafael J. Wysocki 0 siblings, 0 replies; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-12 0:24 UTC (permalink / raw) To: Alan; +Cc: Pavel Machek, Arjan van de Ven, nigel, LKML On Monday, 12 February 2007 01:28, Alan wrote: > > +PM support: Since Linux is used on many portable and desktop systems, your > > + driver is likely to be used on such a system and therefore it > > + should support basic power management by implementing, if > > + necessary, the .suspend and .resume methods used during the > > + system-wide suspend and resume transitions. You should verify > > + that your driver correctly handles the suspend and resume, but > > + if you are unable to ensure that, please at least define the > > + .suspend method returning the -ENOSYS ("Function not > > + implemented") error. Note, however, that in such a case your > > + submission is likely to be suspended and only resumed when the > > + driver correctly handles this feature. > > I'd lose the last bit. Just end it at "error.", there are going to be > people who produce good reasons not to handle suspend/resume. OK, I will. ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 21:02 ` Alan 2007-02-11 23:04 ` Rafael J. Wysocki @ 2007-02-11 23:10 ` Nigel Cunningham 2007-02-11 23:16 ` Rafael J. Wysocki 2007-02-11 23:21 ` Pavel Machek 1 sibling, 2 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 23:10 UTC (permalink / raw) To: Alan; +Cc: Pavel Machek, Rafael J. Wysocki, Arjan van de Ven, LKML Hi. On Sun, 2007-02-11 at 21:02 +0000, Alan wrote: > > > "If the device requires that, implement .suspend and .resume or at least > > > define .suspend that will always return -ENOSYS (then people will know they > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > whether or not the device requires .suspend and .resume, define .suspend that > > > will always return -ENOSYS." > > > > Sounds ok to me. Where should this text go? > > Documentation/SubmittingDrivers ? > > And testing/submitting drivers, perhaps with additional text in that to > make it clear we want suspend/resume support or good excuses > > "Please verify your driver correctly handles suspend and resume. If it > does not your patch submission is likely to be suspended and only resume > when the driver correctly handles this feature" Maybe make it explicit that testing should be done for both suspend to ram and to disk, and with the following usage scenarios as applicable? - built in; - modular, loaded while suspending but not loaded prior to resume from disk; - modular, loaded while suspending and loaded prior to resume from disk; Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:10 ` Nigel Cunningham @ 2007-02-11 23:16 ` Rafael J. Wysocki 2007-02-11 23:22 ` Nigel Cunningham 2007-02-11 23:21 ` Pavel Machek 1 sibling, 1 reply; 77+ messages in thread From: Rafael J. Wysocki @ 2007-02-11 23:16 UTC (permalink / raw) To: nigel; +Cc: Alan, Pavel Machek, Arjan van de Ven, LKML On Monday, 12 February 2007 00:10, Nigel Cunningham wrote: > Hi. > > On Sun, 2007-02-11 at 21:02 +0000, Alan wrote: > > > > "If the device requires that, implement .suspend and .resume or at least > > > > define .suspend that will always return -ENOSYS (then people will know they > > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > > whether or not the device requires .suspend and .resume, define .suspend that > > > > will always return -ENOSYS." > > > > > > Sounds ok to me. Where should this text go? > > > Documentation/SubmittingDrivers ? > > > > And testing/submitting drivers, perhaps with additional text in that to > > make it clear we want suspend/resume support or good excuses > > > > "Please verify your driver correctly handles suspend and resume. If it > > does not your patch submission is likely to be suspended and only resume > > when the driver correctly handles this feature" > > Maybe make it explicit that testing should be done for both suspend to > ram and to disk, and with the following usage scenarios as applicable? > > - built in; > - modular, loaded while suspending but not loaded prior to resume from > disk; > - modular, loaded while suspending and loaded prior to resume from disk; I think we should state the general rule in Documentation/SubmittingDrivers and give more details in Documentation/power/devices.txt Greetings, Rafael ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:16 ` Rafael J. Wysocki @ 2007-02-11 23:22 ` Nigel Cunningham 2007-02-11 23:23 ` Pavel Machek 0 siblings, 1 reply; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 23:22 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Alan, Pavel Machek, Arjan van de Ven, LKML Hi. On Mon, 2007-02-12 at 00:16 +0100, Rafael J. Wysocki wrote: > On Monday, 12 February 2007 00:10, Nigel Cunningham wrote: > > Hi. > > > > On Sun, 2007-02-11 at 21:02 +0000, Alan wrote: > > > > > "If the device requires that, implement .suspend and .resume or at least > > > > > define .suspend that will always return -ENOSYS (then people will know they > > > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > > > whether or not the device requires .suspend and .resume, define .suspend that > > > > > will always return -ENOSYS." > > > > > > > > Sounds ok to me. Where should this text go? > > > > Documentation/SubmittingDrivers ? > > > > > > And testing/submitting drivers, perhaps with additional text in that to > > > make it clear we want suspend/resume support or good excuses > > > > > > "Please verify your driver correctly handles suspend and resume. If it > > > does not your patch submission is likely to be suspended and only resume > > > when the driver correctly handles this feature" > > > > Maybe make it explicit that testing should be done for both suspend to > > ram and to disk, and with the following usage scenarios as applicable? > > > > - built in; > > - modular, loaded while suspending but not loaded prior to resume from > > disk; > > - modular, loaded while suspending and loaded prior to resume from disk; > > I think we should state the general rule in Documentation/SubmittingDrivers > and give more details in Documentation/power/devices.txt Sounds good. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:22 ` Nigel Cunningham @ 2007-02-11 23:23 ` Pavel Machek 0 siblings, 0 replies; 77+ messages in thread From: Pavel Machek @ 2007-02-11 23:23 UTC (permalink / raw) To: Nigel Cunningham; +Cc: Rafael J. Wysocki, Alan, Arjan van de Ven, LKML Hi! > > > - built in; > > > - modular, loaded while suspending but not loaded prior to resume from > > > disk; > > > - modular, loaded while suspending and loaded prior to resume from disk; > > > > I think we should state the general rule in Documentation/SubmittingDrivers > > and give more details in Documentation/power/devices.txt > > Sounds good. Ok, so who does the patch? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:10 ` Nigel Cunningham 2007-02-11 23:16 ` Rafael J. Wysocki @ 2007-02-11 23:21 ` Pavel Machek 2007-02-11 23:29 ` Nigel Cunningham 1 sibling, 1 reply; 77+ messages in thread From: Pavel Machek @ 2007-02-11 23:21 UTC (permalink / raw) To: Nigel Cunningham; +Cc: Alan, Rafael J. Wysocki, Arjan van de Ven, LKML Hi! > > > > define .suspend that will always return -ENOSYS (then people will know they > > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > > whether or not the device requires .suspend and .resume, define .suspend that > > > > will always return -ENOSYS." > > > > > > Sounds ok to me. Where should this text go? > > > Documentation/SubmittingDrivers ? > > > > And testing/submitting drivers, perhaps with additional text in that to > > make it clear we want suspend/resume support or good excuses > > > > "Please verify your driver correctly handles suspend and resume. If it > > does not your patch submission is likely to be suspended and only resume > > when the driver correctly handles this feature" > > Maybe make it explicit that testing should be done for both suspend to > ram and to disk, and with the following usage scenarios as > applicable? Well, for many people s2ram does not work even today... so requiring them to test it is slightly draconian. > - built in; > - modular, loaded while suspending but not loaded prior to resume from > disk; These two should be equivalent. > - modular, loaded while suspending and loaded prior to resume from disk; Ok.. but I'm not sure how many people will actually test it _that_ thoroughly. "Try to test it" is good enough for a first version. When suspend is in better shape, we can ask for more. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 23:21 ` Pavel Machek @ 2007-02-11 23:29 ` Nigel Cunningham 0 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-11 23:29 UTC (permalink / raw) To: Pavel Machek; +Cc: Alan, Rafael J. Wysocki, Arjan van de Ven, LKML Hi. On Mon, 2007-02-12 at 00:21 +0100, Pavel Machek wrote: > Hi! > > > > > > define .suspend that will always return -ENOSYS (then people will know they > > > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > > > whether or not the device requires .suspend and .resume, define .suspend that > > > > > will always return -ENOSYS." > > > > > > > > Sounds ok to me. Where should this text go? > > > > Documentation/SubmittingDrivers ? > > > > > > And testing/submitting drivers, perhaps with additional text in that to > > > make it clear we want suspend/resume support or good excuses > > > > > > "Please verify your driver correctly handles suspend and resume. If it > > > does not your patch submission is likely to be suspended and only resume > > > when the driver correctly handles this feature" > > > > Maybe make it explicit that testing should be done for both suspend to > > ram and to disk, and with the following usage scenarios as > > applicable? > > Well, for many people s2ram does not work even today... so requiring > them to test it is slightly draconian. > > > - built in; > > - modular, loaded while suspending but not loaded prior to resume from > > disk; > > These two should be equivalent. No. The differences are: Built in: The initcalls will have run, but the driver may or may not actually have been used, depending on whether it's used before we start the resume. It should probably be tested with both having been used and not having been used. Modular, loaded prior to suspending but not prior to resuming: At resume time, will still be in whatever config the bios puts it in. No Linux driver code will have touched it. Modular, loaded prior to suspending and resuming: Should be equivalent to built in (module initcalls will have run), but may vary if there's some difference in code/timing between being a module and built in. (This shouldn't happen, but that's the point to testing). > > - modular, loaded while suspending and loaded prior to resume from disk; > > Ok.. but I'm not sure how many people will actually test it _that_ > thoroughly. "Try to test it" is good enough for a first version. When > suspend is in better shape, we can ask for more. I'd prefer to ask for what should be done from the start. Will we expect people to go back and retest if we change the rules, or do we prefer them to complain "You didn't adequately point out the testing I needed to do, and I got all these complaints from my users!" Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-11 19:42 ` Pavel Machek 2007-02-11 21:02 ` Alan @ 2007-02-11 22:21 ` Tilman Schmidt 1 sibling, 0 replies; 77+ messages in thread From: Tilman Schmidt @ 2007-02-11 22:21 UTC (permalink / raw) To: Pavel Machek; +Cc: Rafael J. Wysocki, Arjan van de Ven, nigel, LKML [-- Attachment #1: Type: text/plain, Size: 735 bytes --] Am 11.02.2007 20:42 schrieb Pavel Machek: [...] >> What about this: >> >> "If the device requires that, implement .suspend and .resume or at least >> define .suspend that will always return -ENOSYS (then people will know they >> have to unload the driver before the suspend). Similarly, if you aren't sure >> whether or not the device requires .suspend and .resume, define .suspend that >> will always return -ENOSYS." > > Sounds ok to me. Where should this text go? > Documentation/SubmittingDrivers ? Documentation/power/devices.txt? -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany - In theory, there is no difference between theory and practice. In practice, there is. [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 253 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 22:20 ` Rafael J. Wysocki 2007-02-10 22:37 ` Nigel Cunningham 2007-02-11 19:42 ` Pavel Machek @ 2007-02-12 8:49 ` Geert Uytterhoeven 2007-02-12 15:04 ` Pavel Machek 2 siblings, 1 reply; 77+ messages in thread From: Geert Uytterhoeven @ 2007-02-12 8:49 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: Pavel Machek, Arjan van de Ven, nigel, LKML On Sat, 10 Feb 2007, Rafael J. Wysocki wrote: > What about this: > > "If the device requires that, implement .suspend and .resume or at least ^^^^^^^^ > define .suspend that will always return -ENOSYS (then people will know they ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > have to unload the driver before the suspend). Similarly, if you aren't sure > whether or not the device requires .suspend and .resume, define .suspend that ^^^^^^^^^^^^^^^^^^^^ > will always return -ENOSYS." ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? It's nicer if you don't have to implement dummy functions at all. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 8:49 ` Geert Uytterhoeven @ 2007-02-12 15:04 ` Pavel Machek 2007-02-12 15:57 ` Geert Uytterhoeven 0 siblings, 1 reply; 77+ messages in thread From: Pavel Machek @ 2007-02-12 15:04 UTC (permalink / raw) To: Geert Uytterhoeven; +Cc: Rafael J. Wysocki, Arjan van de Ven, nigel, LKML Hi! > > "If the device requires that, implement .suspend and .resume or at least > ^^^^^^^^ > > define .suspend that will always return -ENOSYS (then people will know they > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > have to unload the driver before the suspend). Similarly, if you aren't sure > > whether or not the device requires .suspend and .resume, define .suspend that > ^^^^^^^^^^^^^^^^^^^^ > > will always return -ENOSYS." > ^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? > It's nicer if you don't have to implement dummy functions at all. Unfortunately, drivers currently assume "NULL == nothing is needed", so we'd have t do big search & replace... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 15:04 ` Pavel Machek @ 2007-02-12 15:57 ` Geert Uytterhoeven 2007-02-12 16:55 ` Pavel Machek ` (2 more replies) 0 siblings, 3 replies; 77+ messages in thread From: Geert Uytterhoeven @ 2007-02-12 15:57 UTC (permalink / raw) To: Pavel Machek; +Cc: Rafael J. Wysocki, Arjan van de Ven, nigel, LKML On Mon, 12 Feb 2007, Pavel Machek wrote: > > > "If the device requires that, implement .suspend and .resume or at least > > ^^^^^^^^ > > > define .suspend that will always return -ENOSYS (then people will know they > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > whether or not the device requires .suspend and .resume, define .suspend that > > ^^^^^^^^^^^^^^^^^^^^ > > > will always return -ENOSYS." > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? > > It's nicer if you don't have to implement dummy functions at all. > > Unfortunately, drivers currently assume "NULL == nothing is needed", > so we'd have t do big search & replace... Which means you also cannot easily keep track of which driver supports suspend/resume and which doesn't, as there will always be drivers where a missing suspend/resume function is correct. Wouldn't it be more sensible to have .suspend = suspend_nothing_to_do instead, and reserve NULL for `not yet implemented'? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 15:57 ` Geert Uytterhoeven @ 2007-02-12 16:55 ` Pavel Machek 2007-02-12 20:38 ` Nigel Cunningham 2007-02-13 10:02 ` Tilman Schmidt 2 siblings, 0 replies; 77+ messages in thread From: Pavel Machek @ 2007-02-12 16:55 UTC (permalink / raw) To: Geert Uytterhoeven; +Cc: Rafael J. Wysocki, Arjan van de Ven, nigel, LKML Hi! > > > > "If the device requires that, implement .suspend and .resume or at least > > > ^^^^^^^^ > > > > define .suspend that will always return -ENOSYS (then people will know they > > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > > whether or not the device requires .suspend and .resume, define .suspend that > > > ^^^^^^^^^^^^^^^^^^^^ > > > > will always return -ENOSYS." > > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? > > > It's nicer if you don't have to implement dummy functions at all. > > > > Unfortunately, drivers currently assume "NULL == nothing is needed", > > so we'd have t do big search & replace... > > Which means you also cannot easily keep track of which driver supports > suspend/resume and which doesn't, as there will always be drivers where a > missing suspend/resume function is correct. > > Wouldn't it be more sensible to have > > .suspend = suspend_nothing_to_do > > instead, and reserve NULL for `not yet implemented'? It would be. Patch would be welcome :-). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 15:57 ` Geert Uytterhoeven 2007-02-12 16:55 ` Pavel Machek @ 2007-02-12 20:38 ` Nigel Cunningham 2007-02-13 10:02 ` Tilman Schmidt 2 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-12 20:38 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Pavel Machek, Rafael J. Wysocki, Arjan van de Ven, LKML Hi. On Mon, 2007-02-12 at 16:57 +0100, Geert Uytterhoeven wrote: > On Mon, 12 Feb 2007, Pavel Machek wrote: > > > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? > > > It's nicer if you don't have to implement dummy functions at all. > > > > Unfortunately, drivers currently assume "NULL == nothing is needed", > > so we'd have t do big search & replace... > > Which means you also cannot easily keep track of which driver supports > suspend/resume and which doesn't, as there will always be drivers where a > missing suspend/resume function is correct. > > Wouldn't it be more sensible to have > > .suspend = suspend_nothing_to_do > > instead, and reserve NULL for `not yet implemented'? Agreed. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-12 15:57 ` Geert Uytterhoeven 2007-02-12 16:55 ` Pavel Machek 2007-02-12 20:38 ` Nigel Cunningham @ 2007-02-13 10:02 ` Tilman Schmidt 2 siblings, 0 replies; 77+ messages in thread From: Tilman Schmidt @ 2007-02-13 10:02 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Pavel Machek, Rafael J. Wysocki, Arjan van de Ven, nigel, LKML [-- Attachment #1: Type: text/plain, Size: 1200 bytes --] Geert Uytterhoeven schrieb: > On Mon, 12 Feb 2007, Pavel Machek wrote: >> > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? >> > It's nicer if you don't have to implement dummy functions at all. >> >> Unfortunately, drivers currently assume "NULL == nothing is needed", More often than not they assume nothing of the kind. >> so we'd have t do big search & replace... > > Which means you also cannot easily keep track of which driver supports > suspend/resume and which doesn't, as there will always be drivers where a > missing suspend/resume function is correct. I think those are rare exceptions. They could and should be asked to make this statement explicit, as you propose: > Wouldn't it be more sensible to have > > .suspend = suspend_nothing_to_do > > instead, and reserve NULL for `not yet implemented'? NULL is already taken for 'don't know'. So *two* new values are needed, one for "nothing to do" and one for "not supported". -- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite) [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 250 bytes --] ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-09 21:57 NAK new drivers without proper power management? Nigel Cunningham 2007-02-09 22:17 ` Arjan van de Ven @ 2007-02-10 3:42 ` Matthew Garrett 2007-02-10 4:42 ` Nigel Cunningham 1 sibling, 1 reply; 77+ messages in thread From: Matthew Garrett @ 2007-02-10 3:42 UTC (permalink / raw) To: Nigel Cunningham; +Cc: LKML On Sat, Feb 10, 2007 at 08:57:49AM +1100, Nigel Cunningham wrote: > Can we start to NAK new drivers that don't have proper power management > implemented? There really is no excuse for writing a new driver and not > putting .suspend and .resume methods in anymore, is there? The PCI layer is able to deal with drivers that have no PM methods in the most simple case. -- Matthew Garrett | mjg59@srcf.ucam.org ^ permalink raw reply [flat|nested] 77+ messages in thread
* Re: NAK new drivers without proper power management? 2007-02-10 3:42 ` Matthew Garrett @ 2007-02-10 4:42 ` Nigel Cunningham 0 siblings, 0 replies; 77+ messages in thread From: Nigel Cunningham @ 2007-02-10 4:42 UTC (permalink / raw) To: Matthew Garrett; +Cc: LKML Hi. On Sat, 2007-02-10 at 03:42 +0000, Matthew Garrett wrote: > On Sat, Feb 10, 2007 at 08:57:49AM +1100, Nigel Cunningham wrote: > > > Can we start to NAK new drivers that don't have proper power management > > implemented? There really is no excuse for writing a new driver and not > > putting .suspend and .resume methods in anymore, is there? > > The PCI layer is able to deal with drivers that have no PM methods in > the most simple case. Yeah. I suppose we could use a pm_safe bit flag in struct device_driver and/or struct pci_driver. I have other things to do right now, but will seek to understand the relationship between those structs better later. Regards, Nigel ^ permalink raw reply [flat|nested] 77+ messages in thread
end of thread, other threads:[~2007-03-08 23:35 UTC | newest] Thread overview: 77+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2007-02-09 21:57 NAK new drivers without proper power management? Nigel Cunningham 2007-02-09 22:17 ` Arjan van de Ven 2007-02-09 22:26 ` Nigel Cunningham 2007-02-09 22:44 ` Rafael J. Wysocki 2007-02-09 22:44 ` Rafael J. Wysocki 2007-02-09 22:51 ` Nigel Cunningham 2007-02-09 22:51 ` Nigel Cunningham 2007-02-09 23:12 ` Rafael J. Wysocki 2007-02-09 23:12 ` Rafael J. Wysocki 2007-02-09 23:28 ` Nigel Cunningham 2007-02-09 23:28 ` Nigel Cunningham 2007-02-10 0:12 ` Rafael J. Wysocki 2007-02-10 0:12 ` Rafael J. Wysocki 2007-02-10 0:25 ` Jeff Garzik 2007-02-10 6:43 ` Willy Tarreau 2007-02-10 23:52 ` Tilman Schmidt 2007-02-10 7:15 ` Arjan van de Ven 2007-02-10 19:38 ` Pavel Machek 2007-02-10 22:20 ` Rafael J. Wysocki 2007-02-10 22:37 ` Nigel Cunningham 2007-02-10 23:45 ` Tilman Schmidt 2007-02-11 0:27 ` Rafael J. Wysocki 2007-02-11 22:41 ` Nigel Cunningham 2007-02-13 15:55 ` Mark Lord 2007-02-13 16:06 ` Christoph Hellwig 2007-02-11 22:37 ` Nigel Cunningham 2007-02-12 0:10 ` Tilman Schmidt 2007-02-12 0:20 ` Rafael J. Wysocki 2007-02-12 4:08 ` Nigel Cunningham 2007-02-12 20:06 ` Rafael J. Wysocki 2007-02-12 22:38 ` Nigel Cunningham 2007-03-03 22:48 ` Suspend/resume semantics for ISDN drivers (was: NAK new drivers without proper power management?) Tilman Schmidt 2007-03-04 19:04 ` Rafael J. Wysocki 2007-03-08 23:35 ` Pavel Machek 2007-02-11 6:46 ` NAK new drivers without proper power management? Willy Tarreau 2007-02-11 13:04 ` Rafael J. Wysocki 2007-02-11 22:47 ` Nigel Cunningham 2007-02-11 22:57 ` Manu Abraham 2007-02-11 23:20 ` Nigel Cunningham 2007-02-11 23:25 ` Manu Abraham 2007-02-11 23:29 ` Pavel Machek 2007-02-11 23:33 ` Nigel Cunningham 2007-02-12 16:52 ` Pavel Machek 2007-02-12 20:31 ` Rafael J. Wysocki 2007-02-12 20:58 ` Pavel Machek 2007-02-12 21:01 ` Rafael J. Wysocki 2007-02-12 21:24 ` Nigel Cunningham 2007-02-12 21:43 ` Rafael J. Wysocki 2007-02-13 9:42 ` Tilman Schmidt 2007-02-13 19:24 ` Rafael J. Wysocki 2007-02-14 23:45 ` Stefan Richter 2007-02-12 9:45 ` Arjan van de Ven 2007-02-12 12:59 ` Gerhard Mack 2007-02-12 20:20 ` Willy Tarreau 2007-02-13 15:23 ` Brad Campbell 2007-02-12 20:46 ` Rafael J. Wysocki 2007-02-12 13:51 ` Tino Keitel 2007-02-11 19:42 ` Pavel Machek 2007-02-11 21:02 ` Alan 2007-02-11 23:04 ` Rafael J. Wysocki 2007-02-12 0:28 ` Alan 2007-02-12 0:24 ` Rafael J. Wysocki 2007-02-11 23:10 ` Nigel Cunningham 2007-02-11 23:16 ` Rafael J. Wysocki 2007-02-11 23:22 ` Nigel Cunningham 2007-02-11 23:23 ` Pavel Machek 2007-02-11 23:21 ` Pavel Machek 2007-02-11 23:29 ` Nigel Cunningham 2007-02-11 22:21 ` Tilman Schmidt 2007-02-12 8:49 ` Geert Uytterhoeven 2007-02-12 15:04 ` Pavel Machek 2007-02-12 15:57 ` Geert Uytterhoeven 2007-02-12 16:55 ` Pavel Machek 2007-02-12 20:38 ` Nigel Cunningham 2007-02-13 10:02 ` Tilman Schmidt 2007-02-10 3:42 ` Matthew Garrett 2007-02-10 4:42 ` Nigel Cunningham
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