[Dropping Jammy since his email bounces] On 1 November 2016 at 15:47, Alex Deucher <alexdeucher at gmail.com> wrote: > On Tue, Nov 1, 2016 at 11:42 AM, Emil Velikov <emil.l.velikov at gmail.com> > wrote: >> From: Emil Velikov <emil.velikov at collabora.com> >> >> 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 <Jammy.Zhou at amd.com> >> Cc: Michel Dänzer <michel.daenzer at amd.com> >> Cc: Bjorn Helgaas <bhelgaas at google.com> >> Cc: linux-pci at vger.kernel.org >> Cc: linux-kernel at vger.kernel.org >> Signed-off-by: Emil Velikov <emil.velikov at collabora.com> > > Reviewed-by: Alex Deucher <alexander.deucher at amd.com> > 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
