Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933290AbcKHL14 (ORCPT ); Tue, 8 Nov 2016 06:27:56 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:35954 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933209AbcKHL1x (ORCPT ); Tue, 8 Nov 2016 06:27:53 -0500 MIME-Version: 1.0 In-Reply-To: References: <20161101154232.6451-1-emil.l.velikov@gmail.com> From: Emil Velikov Date: Tue, 8 Nov 2016 11:27:37 +0000 Message-ID: Subject: Re: [PATCH] PCI: create revision file in sysfs To: Alex Deucher Cc: Maling list - DRI developers , =?UTF-8?Q?Michel_D=C3=A4nzer?= , LKML , Linux PCI , Bjorn Helgaas Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id uA8BSQNh006823 Content-Length: 1532 Lines: 42 [Dropping Jammy since his email bounces] On 1 November 2016 at 15:47, Alex Deucher wrote: > On Tue, Nov 1, 2016 at 11:42 AM, Emil Velikov wrote: >> From: Emil Velikov >> >> Currently the revision isn't available via sysfs/libudev thus if one >> wants to know the value they need to read through the config file. >> >> This in itself wakes/powers up the device, causing unwanted delay >> since it can be quite costly. >> >> Expose the revision as a separate file, just like we do for the device, >> vendor, their subsystem version and class. >> >> Cc: Jammy Zhou >> Cc: Michel Dänzer >> Cc: Bjorn Helgaas >> Cc: linux-pci@vger.kernel.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Emil Velikov > > Reviewed-by: Alex Deucher > Thanks Alex. Gents, to elaborate a bit: When using the Mesa drivers alongside firefox [1] (since Mesa 13.0), glxinfo (Mesa 10.0) and others, all the GPUs* will be awaken, causing unwanted delays and increased power usage. >From the userspace POV we have two distinct users who require the revision file - libdrm and libpciaccess. * The latter would even wake up _all_ the devices located on a PCI bus ! Let me know if you'd like the above in the patch summary, meanwhile I'll poke and collect a few more ack/r-b/t-b. Thanks Emil [1] https://bugs.freedesktop.org/show_bug.cgi?id=98502