* [PATCH] usb: gadget/legacy/ether: assume saner default power mode @ 2021-09-16 14:56 Andreas Bauer 2021-09-16 15:36 ` Greg KH 2021-09-17 5:28 ` Felipe Balbi 0 siblings, 2 replies; 6+ messages in thread From: Andreas Bauer @ 2021-09-16 14:56 UTC (permalink / raw) To: linux-usb I propose the included patch to the OTG USB ethernet gadget code: Report default of bus powered and 500mA bMaxPower consumption. Reason: The USB spec requires all devices consuming more than 100mA from the bus to report in this manner. Devices such as Rpi Zero can operate in this mode and will then falsly report being self-powered when they are not. The more sane default is to report being 500mA bus-powered than being self-powered This patch was born from an issue within the Raspberry Pi Zero ecosystem, therefore I would invite comment regarding other usage of this OTG code. Best regards, Andreas $ diff -u linux-5.14.2/drivers/usb/gadget/legacy/ether.c.orig linux-5.14.2/drivers/usb/gadget/legacy/ether.c --- linux-5.14.2/drivers/usb/gadget/legacy/ether.c.orig 2021-09-08 13:52:41.000000000 +0700 +++ linux-5.14.2/drivers/usb/gadget/legacy/ether.c 2021-09-16 21:25:06.782958554 +0700 @@ -296,7 +296,8 @@ /* .label = f(hardware) */ .bConfigurationValue = 1, /* .iConfiguration = DYNAMIC */ - .bmAttributes = USB_CONFIG_ATT_SELFPOWER, + .bmAttributes = 0, /* bus powered implied */ + .bMaxPower = 250, /* 500mA in 2mA units */ }; /*-------------------------------------------------------------------------*/ ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] usb: gadget/legacy/ether: assume saner default power mode 2021-09-16 14:56 [PATCH] usb: gadget/legacy/ether: assume saner default power mode Andreas Bauer @ 2021-09-16 15:36 ` Greg KH 2021-09-17 5:28 ` Felipe Balbi 1 sibling, 0 replies; 6+ messages in thread From: Greg KH @ 2021-09-16 15:36 UTC (permalink / raw) To: Andreas Bauer; +Cc: linux-usb On Thu, Sep 16, 2021 at 09:56:15PM +0700, Andreas Bauer wrote: > > I propose the included patch to the OTG USB ethernet gadget code: > > Report default of bus powered and 500mA bMaxPower consumption. > > Reason: > > The USB spec requires all devices consuming more than 100mA from > the bus to report in this manner. Devices such as Rpi Zero can operate > in this mode and will then falsly report being self-powered when they > are not. > > The more sane default is to report being 500mA bus-powered than being > self-powered > > This patch was born from an issue within the Raspberry Pi Zero ecosystem, > therefore I would invite comment regarding other usage of this OTG code. > > Best regards, > > Andreas > > $ diff -u linux-5.14.2/drivers/usb/gadget/legacy/ether.c.orig linux-5.14.2/drivers/usb/gadget/legacy/ether.c > --- linux-5.14.2/drivers/usb/gadget/legacy/ether.c.orig 2021-09-08 13:52:41.000000000 +0700 > +++ linux-5.14.2/drivers/usb/gadget/legacy/ether.c 2021-09-16 21:25:06.782958554 +0700 > @@ -296,7 +296,8 @@ > /* .label = f(hardware) */ > .bConfigurationValue = 1, > /* .iConfiguration = DYNAMIC */ > - .bmAttributes = USB_CONFIG_ATT_SELFPOWER, > + .bmAttributes = 0, /* bus powered implied */ > + .bMaxPower = 250, /* 500mA in 2mA units */ > }; > > /*-------------------------------------------------------------------------*/ Hi, This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him a patch that has triggered this response. He used to manually respond to these common problems, but in order to save his sanity (he kept writing the same thing over and over, yet to different people), I was created. Hopefully you will not take offence and will fix the problem in your patch and resubmit it so that it can be accepted into the Linux kernel tree. You are receiving this message because of the following common error(s) as indicated below: - Your patch does not have a Signed-off-by: line. Please read the kernel file, Documentation/SubmittingPatches and resend it after adding that line. Note, the line needs to be in the body of the email, before the patch, not at the bottom of the patch or in the email signature. - You did not specify a description of why the patch is needed, or possibly, any description at all, in the email body. Please read the section entitled "The canonical patch format" in the kernel file, Documentation/SubmittingPatches for what is needed in order to properly describe the change. If you wish to discuss this problem further, or you have questions about how to resolve this issue, please feel free to respond to this email and Greg will reply once he has dug out from the pending patches received from other developers. thanks, greg k-h's patch email bot ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] usb: gadget/legacy/ether: assume saner default power mode 2021-09-16 14:56 [PATCH] usb: gadget/legacy/ether: assume saner default power mode Andreas Bauer 2021-09-16 15:36 ` Greg KH @ 2021-09-17 5:28 ` Felipe Balbi 2021-09-17 7:15 ` Andreas Bauer 1 sibling, 1 reply; 6+ messages in thread From: Felipe Balbi @ 2021-09-17 5:28 UTC (permalink / raw) To: Andreas Bauer; +Cc: linux-usb Hi, Andreas Bauer <andreas.bauer.nexus@gmail.com> writes: > I propose the included patch to the OTG USB ethernet gadget code: > > Report default of bus powered and 500mA bMaxPower consumption. > > Reason: > > The USB spec requires all devices consuming more than 100mA from > the bus to report in this manner. Devices such as Rpi Zero can operate > in this mode and will then falsly report being self-powered when they > are not. > > The more sane default is to report being 500mA bus-powered than being > self-powered > > This patch was born from an issue within the Raspberry Pi Zero ecosystem, > therefore I would invite comment regarding other usage of this OTG code. Have a look at other commits to get examples of how to write commits for upstream. You're missing your Signed-off-by, adding extra unnecessary spaces and making your signature show up in the commit log. All of these are described in kernel documentation this (https://www.kernel.org/doc/html/latest/process/submitting-patches.html) is a good starting point. > $ diff -u linux-5.14.2/drivers/usb/gadget/legacy/ether.c.orig linux-5.14.2/drivers/usb/gadget/legacy/ether.c > --- linux-5.14.2/drivers/usb/gadget/legacy/ether.c.orig 2021-09-08 13:52:41.000000000 +0700 > +++ linux-5.14.2/drivers/usb/gadget/legacy/ether.c 2021-09-16 21:25:06.782958554 +0700 > @@ -296,7 +296,8 @@ > /* .label = f(hardware) */ > .bConfigurationValue = 1, > /* .iConfiguration = DYNAMIC */ > - .bmAttributes = USB_CONFIG_ATT_SELFPOWER, > + .bmAttributes = 0, /* bus powered implied */ > + .bMaxPower = 250, /* 500mA in 2mA units */ right, your "sane" default now prevents this gadget driver from working behind bus powered hubs. Considering that a linux-based device is likely to have its own battery, this is not really a sane default. The default value of "self powered", seems much saner ;-) -- balbi ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] usb: gadget/legacy/ether: assume saner default power mode 2021-09-17 5:28 ` Felipe Balbi @ 2021-09-17 7:15 ` Andreas Bauer 2021-09-17 8:29 ` Felipe Balbi 0 siblings, 1 reply; 6+ messages in thread From: Andreas Bauer @ 2021-09-17 7:15 UTC (permalink / raw) To: Felipe Balbi; +Cc: linux-usb Am Fri, Sep 17, 2021 at 08:28:16AM +0300 schrieb Felipe Balbi: > Have a look at other commits to get examples of how to write commits for > upstream. You're missing your Signed-off-by, adding extra unnecessary > spaces and making your signature show up in the commit log. All of > these are described in kernel documentation this > (https://www.kernel.org/doc/html/latest/process/submitting-patches.html) > is a good starting point. I apologize, this was my first try at contributing based on what I observed on this list. Will fix all mentioned points and consult the documentation before trying again. > > - .bmAttributes = USB_CONFIG_ATT_SELFPOWER, > > + .bmAttributes = 0, /* bus powered implied */ > > + .bMaxPower = 250, /* 500mA in 2mA units */ > > right, your "sane" default now prevents this gadget driver from working > behind bus powered hubs. Considering that a linux-based device is likely > to have its own battery, this is not really a sane default. The linux-based battery-powered device I have here (Android) charges its battery and is thus bus-powered while in gadget mode. Are there really a lot of devices that use gadget mode and do NOT draw power from the USB bus? Honest question, I don't know the answer. > The default value of "self powered", seems much saner ;-) It violates USB specification as is for most cases I reckon. It also maximize functionality when the host does not enforce USB spec which mostly seems to be the case. Would a CONFIG option here make sense to differentiate between bus-powered devices and self-powered ones? This would probably affect most OTG drivers... regards, Andreas ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] usb: gadget/legacy/ether: assume saner default power mode 2021-09-17 7:15 ` Andreas Bauer @ 2021-09-17 8:29 ` Felipe Balbi 2021-09-17 17:12 ` Andreas Bauer 0 siblings, 1 reply; 6+ messages in thread From: Felipe Balbi @ 2021-09-17 8:29 UTC (permalink / raw) To: Andreas Bauer; +Cc: linux-usb Hi, Andreas Bauer <andreas.bauer.nexus@gmail.com> writes: > Am Fri, Sep 17, 2021 at 08:28:16AM +0300 schrieb Felipe Balbi: > >> Have a look at other commits to get examples of how to write commits for >> upstream. You're missing your Signed-off-by, adding extra unnecessary >> spaces and making your signature show up in the commit log. All of >> these are described in kernel documentation this >> (https://www.kernel.org/doc/html/latest/process/submitting-patches.html) >> is a good starting point. > > I apologize, this was my first try at contributing based on what I > observed on this list. Will fix all mentioned points and consult the > documentation before trying again. No worries :) >> > - .bmAttributes = USB_CONFIG_ATT_SELFPOWER, >> > + .bmAttributes = 0, /* bus powered implied */ >> > + .bMaxPower = 250, /* 500mA in 2mA units */ >> >> right, your "sane" default now prevents this gadget driver from working >> behind bus powered hubs. Considering that a linux-based device is likely >> to have its own battery, this is not really a sane default. > > The linux-based battery-powered device I have here (Android) charges its > battery and is thus bus-powered while in gadget mode. that's okay. It's because of this sort of thing that we've switched to a configfs-based approach where we don't need to make assumptions about the application. That's also why the pre-composed gadgets have been moved to the "legacy" directory and we don't take changes to those anymore, unless it's a bugfix, which $subject doesn't appear to be :) > Are there really a lot of devices that use gadget mode and do NOT draw > power from the USB bus? Honest question, I don't know the answer. Finding that out is going to be pretty hard, I'm afraid. >> The default value of "self powered", seems much saner ;-) > > It violates USB specification as is for most cases I reckon. It also > maximize functionality when the host does not enforce USB spec which > mostly seems to be the case. > > Would a CONFIG option here make sense to differentiate between > bus-powered devices and self-powered ones? This would probably affect > most OTG drivers... We have configfs to cope with all of the possible variations, might want to give that a shot? https://www.kernel.org/doc/html/latest/usb/gadget_configfs.html -- balbi ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] usb: gadget/legacy/ether: assume saner default power mode 2021-09-17 8:29 ` Felipe Balbi @ 2021-09-17 17:12 ` Andreas Bauer 0 siblings, 0 replies; 6+ messages in thread From: Andreas Bauer @ 2021-09-17 17:12 UTC (permalink / raw) To: Felipe Balbi; +Cc: linux-usb Am Fri, Sep 17, 2021 at 11:29:02AM +0300 schrieb Felipe Balbi: > that's okay. It's because of this sort of thing that we've switched to a > configfs-based approach where we don't need to make assumptions about > the application. That's also why the pre-composed gadgets have been > moved to the "legacy" directory and we don't take changes to those > anymore, unless it's a bugfix, which $subject doesn't appear to be :) Ok... my intention was to fix something which is wrong, but as always in life, things are complicated. I will not pursue this further. Thanks for your input. > We have configfs to cope with all of the possible variations, might want > to give that a shot? > > https://www.kernel.org/doc/html/latest/usb/gadget_configfs.html Never change a ru.... I will eventually give it a shot ;-) best regards, Andreas ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-09-17 17:12 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-09-16 14:56 [PATCH] usb: gadget/legacy/ether: assume saner default power mode Andreas Bauer 2021-09-16 15:36 ` Greg KH 2021-09-17 5:28 ` Felipe Balbi 2021-09-17 7:15 ` Andreas Bauer 2021-09-17 8:29 ` Felipe Balbi 2021-09-17 17:12 ` Andreas Bauer
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