From: Jean Delvare <khali@linux-fr.org> To: David Hubbard <david.c.hubbard@gmail.com> Cc: Rudolf Marek <r.marek@assembler.cz>, Matthew Garrett <mjg59@srcf.ucam.org>, Ebbert <cebbert@redhat.com>, Chuck@atrpms.net, linux-kernel <linux-kernel@vger.kernel.org>, linux-acpi@vger.kernel.org, Machek <pavel@ucw.cz>, Pavel@atrpms.net, lm-sensors@lm-sensors.org Subject: Re: [lm-sensors] Could the k8temp driver be interfering with ACPI? Date: Tue, 6 Mar 2007 16:10:02 +0100 [thread overview] Message-ID: <20070306161002.2a7d5c74.khali@linux-fr.org> (raw) In-Reply-To: <4dfa50520703051335j34e7d92bl982705adcfd8b1d5@mail.gmail.com> Hi David, On Mon, 5 Mar 2007 13:35:20 -0800, David Hubbard wrote: > > 2* It seems to incur a signficant performance penalty. > > ____request_resource isn't cheap as far as I know. And in the > > absence of conflict, you are even allocating and releasing the resource > > on _each_ I/O operation, which certainly isn't cheap either. Again, it > > is not a blocker point, after all this is a workaround for an improper > > behavior of the acpi subsystem, this performance penalty is the price to > > pay. But there is also a performance penalty for legitimate I/O access, > > which worries me more. > > I thought Rudolf's patch allocated the resource in the driver > (w83627ehf) and ACPI contacted the driver when it could not allocate > the resource. Since ACPI never *really* wants to allocate the > resource, is there a fast-path check it could do? This would help > performance. Alas, I don't think it can work safely. If ACPI doesn't actually allocate the resource, there is a risk that another driver does so between the conflict check and the I/O access. I believe this is the reason why Rudolf used ____request_resource and not __check_region. > I like the virtualized driver method (if it wasn't obvious!) but the > global AML lock works also. It will be interesting to see profiling of > both solutions. In fact Rudolf's solution is nice for LPC chips, however I don't think it can work with SMBus chips. It might intercept the accesses to the SMBus master and be able to emulate it, even though this will be more complex that the W83627EHF case, and I'm not sure about the PCI config space. But ultimately we need to emulate all the chips behind the SMBus, too. The drivers for these chips won't know if they are accessed for real of through the emulation layer, so there is no way they'll remember states, while they might have to (e.g. the W83781D has a bank register too.) The AML lock approach, OTOH, should work fine in all cases as long as the context doesn't need to be remembered across AML "sections". -- Jean Delvare
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From: khali@linux-fr.org (Jean Delvare) To: David Hubbard <david.c.hubbard@gmail.com> Cc: Rudolf Marek <r.marek@assembler.cz>, Matthew Garrett <mjg59@srcf.ucam.org>, Ebbert <cebbert@redhat.com>, Chuck@atrpms.net, linux-kernel <linux-kernel@vger.kernel.org>, linux-acpi@vger.kernel.org, Machek <pavel@ucw.cz>, Pavel@atrpms.net, lm-sensors@lm-sensors.org Subject: [lm-sensors] Could the k8temp driver be interfering with ACPI? Date: Tue, 06 Mar 2007 15:10:02 +0000 [thread overview] Message-ID: <20070306161002.2a7d5c74.khali@linux-fr.org> (raw) In-Reply-To: <4dfa50520703051335j34e7d92bl982705adcfd8b1d5@mail.gmail.com> Hi David, On Mon, 5 Mar 2007 13:35:20 -0800, David Hubbard wrote: > > 2* It seems to incur a signficant performance penalty. > > ____request_resource isn't cheap as far as I know. And in the > > absence of conflict, you are even allocating and releasing the resource > > on _each_ I/O operation, which certainly isn't cheap either. Again, it > > is not a blocker point, after all this is a workaround for an improper > > behavior of the acpi subsystem, this performance penalty is the price to > > pay. But there is also a performance penalty for legitimate I/O access, > > which worries me more. > > I thought Rudolf's patch allocated the resource in the driver > (w83627ehf) and ACPI contacted the driver when it could not allocate > the resource. Since ACPI never *really* wants to allocate the > resource, is there a fast-path check it could do? This would help > performance. Alas, I don't think it can work safely. If ACPI doesn't actually allocate the resource, there is a risk that another driver does so between the conflict check and the I/O access. I believe this is the reason why Rudolf used ____request_resource and not __check_region. > I like the virtualized driver method (if it wasn't obvious!) but the > global AML lock works also. It will be interesting to see profiling of > both solutions. In fact Rudolf's solution is nice for LPC chips, however I don't think it can work with SMBus chips. It might intercept the accesses to the SMBus master and be able to emulate it, even though this will be more complex that the W83627EHF case, and I'm not sure about the PCI config space. But ultimately we need to emulate all the chips behind the SMBus, too. The drivers for these chips won't know if they are accessed for real of through the emulation layer, so there is no way they'll remember states, while they might have to (e.g. the W83781D has a bank register too.) The AML lock approach, OTOH, should work fine in all cases as long as the context doesn't need to be remembered across AML "sections". -- Jean Delvare
next prev parent reply other threads:[~2007-03-06 15:10 UTC|newest] Thread overview: 220+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-02-16 17:31 Could the k8temp driver be interfering with ACPI? Chuck Ebbert 2007-02-16 17:31 ` [lm-sensors] " Chuck Ebbert 2007-02-16 17:57 ` Len Brown 2007-02-16 17:57 ` [lm-sensors] " Len Brown 2007-02-16 18:14 ` Chuck Ebbert 2007-02-16 18:14 ` [lm-sensors] " Chuck Ebbert 2007-02-16 19:59 ` Andi Kleen 2007-02-16 19:59 ` [lm-sensors] " Andi Kleen 2007-02-16 19:31 ` Chuck Ebbert 2007-02-16 19:31 ` [lm-sensors] " Chuck Ebbert 2007-02-18 17:32 ` Jean Delvare 2007-02-18 17:32 ` Jean Delvare 2007-02-18 23:22 ` Andi Kleen 2007-02-18 23:22 ` Andi Kleen 2007-02-17 10:49 ` Rudolf Marek 2007-02-17 10:49 ` [lm-sensors] " Rudolf Marek 2007-02-17 10:49 ` Rudolf Marek 2007-02-17 18:14 ` Chuck Ebbert 2007-02-17 18:14 ` Chuck Ebbert 2007-02-18 17:38 ` Jean Delvare 2007-02-18 17:38 ` Jean Delvare 2007-02-20 15:18 ` Matthew Garrett 2007-02-20 15:18 ` Matthew Garrett 2007-02-20 15:33 ` Luca Tettamanti 2007-02-20 15:33 ` Luca Tettamanti 2007-02-21 14:59 ` Jean Delvare 2007-02-21 14:59 ` Jean Delvare 2007-02-21 15:07 ` Jean Delvare 2007-02-21 15:07 ` Jean Delvare 2007-02-28 21:38 ` Pavel Machek 2007-02-28 21:38 ` Pavel Machek 2007-03-01 14:26 ` Jean Delvare 2007-03-01 14:26 ` [lm-sensors] " Jean Delvare 2007-03-01 14:26 ` Jean Delvare 2007-03-01 17:48 ` Dave Jones 2007-03-01 17:48 ` Dave Jones 2007-03-02 11:27 ` Jean Delvare 2007-03-02 11:27 ` Jean Delvare 2007-03-02 11:31 ` Pavel Machek 2007-03-02 11:31 ` Pavel Machek 2007-03-02 13:37 ` Jean Delvare 2007-03-02 13:37 ` Jean Delvare 2007-03-02 13:47 ` Henrique de Moraes Holschuh 2007-03-02 13:47 ` Henrique de Moraes Holschuh 2007-03-02 13:57 ` Pavel Machek 2007-03-02 13:57 ` Pavel Machek 2007-03-03 6:44 ` Jean Delvare 2007-03-03 6:44 ` Jean Delvare 2007-03-02 11:40 ` Pavel Machek 2007-03-02 11:40 ` Pavel Machek 2007-03-02 11:47 ` Matthew Garrett 2007-03-02 11:47 ` Matthew Garrett 2007-03-02 13:58 ` Pavel Machek 2007-03-02 13:58 ` Pavel Machek 2007-03-02 21:00 ` Jean Delvare 2007-03-02 21:00 ` Jean Delvare 2007-03-02 21:22 ` Henrique de Moraes Holschuh 2007-03-02 21:22 ` Henrique de Moraes Holschuh 2007-04-01 15:39 ` Pavel Machek 2007-04-01 15:39 ` Pavel Machek 2007-04-02 15:48 ` Jean Delvare 2007-04-02 15:48 ` [lm-sensors] " Jean Delvare 2007-04-02 19:22 ` Dave Jones 2007-04-02 19:22 ` [lm-sensors] " Dave Jones 2007-04-03 5:49 ` Jean Delvare 2007-04-03 5:49 ` [lm-sensors] " Jean Delvare 2007-04-02 20:55 ` Moore, Robert 2007-04-02 20:55 ` [lm-sensors] " Moore, Robert 2007-04-02 20:55 ` Moore, Robert 2007-04-03 7:21 ` Jean Delvare 2007-04-03 7:21 ` [lm-sensors] " Jean Delvare 2007-04-03 7:21 ` Jean Delvare 2007-04-04 21:35 ` Moore, Robert 2007-04-04 21:35 ` [lm-sensors] " Moore, Robert 2007-04-04 21:35 ` Moore, Robert 2007-03-02 14:10 ` [lm-sensors] " Jean Delvare 2007-03-02 14:10 ` Jean Delvare 2007-03-02 14:18 ` Matthew Garrett 2007-03-02 14:18 ` Matthew Garrett 2007-03-02 21:04 ` Jean Delvare 2007-03-02 21:04 ` Jean Delvare 2007-03-02 21:12 ` Matthew Garrett 2007-03-02 21:12 ` Matthew Garrett 2007-03-03 9:53 ` Jean Delvare 2007-03-03 9:53 ` Jean Delvare 2007-03-03 15:47 ` David Hubbard 2007-03-03 15:47 ` David Hubbard 2007-03-03 15:50 ` Matthew Garrett 2007-03-03 15:50 ` Matthew Garrett 2007-03-03 17:08 ` Rudolf Marek 2007-03-03 17:08 ` Rudolf Marek 2007-03-04 17:29 ` Rudolf Marek 2007-03-04 17:29 ` Rudolf Marek 2007-03-05 21:16 ` Jean Delvare 2007-03-05 21:16 ` Jean Delvare 2007-03-05 21:35 ` David Hubbard 2007-03-05 21:35 ` David Hubbard 2007-03-06 15:10 ` Jean Delvare [this message] 2007-03-06 15:10 ` Jean Delvare 2007-03-04 10:54 ` Jean Delvare 2007-03-04 10:54 ` Jean Delvare 2007-03-05 22:25 ` Pavel Machek 2007-03-05 22:25 ` Pavel Machek 2007-03-06 7:55 ` Benny Amorsen 2007-03-06 7:55 ` Benny Amorsen 2007-03-06 15:26 ` Jean Delvare 2007-03-06 15:26 ` Jean Delvare 2007-03-06 20:07 ` Stefan Monnier 2007-03-06 20:07 ` Stefan Monnier 2007-03-06 20:07 ` Stefan Monnier 2007-03-06 21:20 ` Pavel Machek 2007-03-06 21:20 ` Pavel Machek 2007-03-06 21:25 ` Moore, Robert 2007-03-06 21:25 ` Moore, Robert 2007-03-06 21:25 ` Moore, Robert 2007-03-18 19:36 ` richardvoigt 2007-03-18 19:36 ` richardvoigt at gmail.com 2007-03-19 7:08 ` Jean Delvare 2007-03-19 7:08 ` Jean Delvare 2007-03-02 22:07 ` Moore, Robert 2007-03-02 22:07 ` Moore, Robert 2007-03-02 22:07 ` Moore, Robert 2007-03-09 7:18 ` Pavel Machek 2007-03-09 7:18 ` Pavel Machek 2007-03-09 10:24 ` Jean Delvare 2007-03-09 10:24 ` Jean Delvare 2007-03-09 10:39 ` Alexey Starikovskiy 2007-03-09 10:39 ` Alexey Starikovskiy 2007-03-09 11:21 ` Pavel Machek 2007-03-09 11:21 ` Pavel Machek 2007-03-09 17:23 ` Jean Delvare 2007-03-09 17:23 ` Jean Delvare 2007-03-09 17:35 ` Alexey Starikovskiy 2007-03-09 17:35 ` Alexey Starikovskiy 2007-03-09 21:03 ` Moore, Robert 2007-03-09 21:03 ` Moore, Robert 2007-03-09 21:03 ` Moore, Robert 2007-03-09 20:56 ` Moore, Robert 2007-03-09 20:56 ` Moore, Robert 2007-03-09 20:56 ` Moore, Robert 2007-03-02 14:22 ` Pavel Machek 2007-03-02 14:22 ` Pavel Machek 2007-03-02 14:03 ` Jean Delvare 2007-03-02 14:03 ` Jean Delvare 2007-03-02 14:24 ` Pavel Machek 2007-03-02 14:24 ` Pavel Machek 2007-03-02 14:57 ` Matthew Garrett 2007-03-02 14:57 ` Matthew Garrett 2007-03-02 21:41 ` Jean Delvare 2007-03-02 21:41 ` Jean Delvare 2007-03-02 21:46 ` Matthew Garrett 2007-03-02 21:46 ` Matthew Garrett 2007-03-06 21:28 ` Jean Delvare 2007-03-06 21:28 ` Jean Delvare 2007-04-13 18:18 ` Bjorn Helgaas 2007-04-13 18:18 ` Bjorn Helgaas 2007-04-13 20:07 ` Pavel Machek 2007-04-13 20:07 ` Pavel Machek 2007-04-13 20:59 ` Bjorn Helgaas 2007-04-13 20:59 ` Bjorn Helgaas 2007-04-15 9:41 ` Jean Delvare 2007-04-15 9:41 ` Jean Delvare 2007-04-15 20:31 ` Bjorn Helgaas 2007-04-15 20:31 ` Bjorn Helgaas 2007-04-15 20:59 ` Luca Tettamanti 2007-04-15 20:59 ` Luca Tettamanti 2007-04-16 0:57 ` Bjorn Helgaas 2007-04-16 0:57 ` Bjorn Helgaas 2007-04-16 21:14 ` Luca Tettamanti 2007-04-16 21:14 ` Luca Tettamanti 2007-04-16 22:28 ` Bjorn Helgaas 2007-04-16 22:28 ` Bjorn Helgaas 2007-04-17 23:50 ` Luca Tettamanti 2007-04-17 23:50 ` Luca Tettamanti 2007-04-22 16:55 ` Luca Tettamanti 2007-04-22 16:55 ` Luca Tettamanti 2007-04-17 10:03 ` Jean Delvare 2007-04-17 10:03 ` Jean Delvare 2007-02-18 22:43 ` Rudolf Marek 2007-02-18 22:43 ` Rudolf Marek 2007-02-20 15:08 ` Chuck Ebbert 2007-02-20 15:08 ` Chuck Ebbert 2007-02-20 19:11 ` Dave Jones 2007-02-20 19:11 ` Dave Jones 2007-02-21 16:17 ` Jean Delvare 2007-02-21 16:17 ` Jean Delvare 2007-02-21 17:37 ` Dave Jones 2007-02-21 17:37 ` Dave Jones 2007-02-21 20:19 ` Dave Jones 2007-02-21 20:19 ` Dave Jones 2007-02-22 16:37 ` Jean Delvare 2007-02-22 16:37 ` Jean Delvare 2007-02-23 7:13 ` Hans de Goede 2007-02-23 7:13 ` [lm-sensors] " Hans de Goede 2007-02-23 7:13 ` Hans de Goede 2007-02-23 7:47 ` Jean Delvare 2007-02-23 7:47 ` Jean Delvare 2007-02-21 14:54 ` Jean Delvare 2007-02-21 14:54 ` Jean Delvare 2007-02-21 16:03 ` Chuck Ebbert 2007-02-21 16:03 ` Chuck Ebbert 2007-02-21 16:22 ` Jean Delvare 2007-02-21 16:22 ` Jean Delvare 2007-02-23 8:08 ` Hans de Goede 2007-02-26 17:24 ` Jean Delvare 2007-02-26 19:03 ` Hans de Goede 2007-02-27 8:45 ` Jean Delvare [not found] <7PvLN-1cj-3@gated-at.bofh.it> [not found] ` <7TEGV-6Jy-39@gated-at.bofh.it> [not found] ` <7TUBX-6TN-5@gated-at.bofh.it> [not found] ` <7UeqX-4QO-17@gated-at.bofh.it> [not found] ` <7UeqZ-4QO-27@gated-at.bofh.it> [not found] ` <7UgM5-np-1@gated-at.bofh.it> [not found] ` <7UgM8-np-11@gated-at.bofh.it> [not found] ` <7UnaS-2xP-9@gated-at.bofh.it> [not found] ` <7UnkC-2JB-9@gated-at.bofh.it> [not found] ` <7Uzcd-49u-3@gated-at.bofh.it> [not found] ` <7UEEN-4xi-3@gated-at.bofh.it> 2007-03-05 13:56 ` Bodo Eggert 2007-03-05 13:56 ` Bodo Eggert 2007-03-05 13:56 ` Bodo Eggert 2007-03-06 15:19 ` Jean Delvare 2007-03-06 15:19 ` Jean Delvare 2007-03-06 20:40 ` Bodo Eggert 2007-03-06 20:40 ` Bodo Eggert 2007-03-07 9:17 ` Jean Delvare 2007-03-07 9:17 ` Jean Delvare 2007-03-07 9:36 ` Pavel Machek 2007-03-07 9:36 ` Pavel Machek 2007-03-07 17:09 ` Bodo Eggert 2007-03-07 17:09 ` Bodo Eggert
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