On 11/11/16 08:59 AM, Bjorn Helgaas wrote: > On Thu, Nov 10, 2016 at 01:14:35PM +0000, Emil Velikov wrote: >> On 10 November 2016 at 07:13, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: >>> On Wed, Nov 09, 2016 at 04:56:07PM +0000, Emil Velikov wrote: >>>> From: Emil Velikov <emil.velikov@xxxxxxxxxxxxx> >>>> >>>> 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 delays. >>>> >>>> There are at least two userspace components which could make use the new >>>> file - libpciaccess and libdrm. At the moment the former will wake up >>>> _every_ PCI device for simple invocation of glxinfo [when using Mesa >>>> 10.0+ drivers]. While the latter [in association with Mesa 13.0] can >>>> lead to 2-3 second delays while starting firefox, thunderbird or >>>> chromium. > > I agree, these unwanted delays are completely unacceptable. My > question is whether we should fix them by exporting more information > from the kernel, or by changing the way the userspace components work. > > It should not take anywhere near 2 seconds to wake up a PCI device. The DRM drivers for AMD/ATI GPUs can take on the order of that to initialize, so a single wakeup might be sufficient for the described symptoms. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
