On Sun, Oct 26, 2014 at 11:31 AM, Alex Deucher <alexdeucher@xxxxxxxxx> wrote: > On Mon, Oct 13, 2014 at 12:11 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: >> [+cc Alex, Christian, dri-devel] >> >> On Sat, Oct 11, 2014 at 1:37 PM, Shawn Starr <shawn.starr@xxxxxxxxxx> wrote: >>> On September 11, 2014 04:26:21 PM Bjorn Helgaas wrote: >>>> [+cc linux-pci] >>>> >>>> On Sat, Aug 2, 2014 at 10:02 AM, Shawn Starr <shawn.starr@xxxxxxxxxx> wrote: >>>> > Hello devs, >>>> > >>>> > There are two issues I am encountering with the PCIe Hotplug driver on my >>>> > Lenovo Laptop (W500). I note this goes back further than 3.15. >>>> > >>>> > It is noted here: >>>> > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id= >>>> > f244d8b623dae7a7bc695b0336f67729b95a9736 >>>> > https://bugzilla.kernel.org/show_bug.cgi?id=79701 >>>> > >>>> > And my open bug here: >>>> > https://bugzilla.kernel.org/show_bug.cgi?id=77261 >>>> > >>>> > 1) If I enable the device to use both the integrated and discrete GPU, >>>> > pciehp will decide to force unload radeon because it puts itself into a >>>> > power saving state, fails back to the Intel integrated GPU in this case >>>> > unless I tell radeon.ko to runpm=0 (no power management, then pciehp wont >>>> > touch it). >>>> > >>>> > 2) If the Radeon GPU resets and you use pci_reset=1 for kernel module >>>> > option, pciehp decides to force unload radeon even though the GPU is >>>> > trying to setup after failing. >>>> > >>>> > Kernel I am using right now: 3.16.0-0.rc7.git3.1.fc21.x86_64 (about to >>>> > boot into snapshot kernel-core-3.16.0-0.rc7.git4.1.fc21.x86_64) >>>> Hi Shawn, >>>> >>>> Thanks for the report and sorry that it got dropped. But I see you're >>>> cc'd on https://bugzilla.kernel.org/show_bug.cgi?id=79701, so you've >>>> probably seen the work there. If you can try out the patches I just >>>> posted, that would be great. >>>> >>>> Bjorn >>> >>> Hi Bjorn, >>> >>> For #1) This is fixed in linux-next (tracking 3.18.0-0.rc0.git1.2.fc22.1.x86_64 >>> nondebug kernel for Fedora). PCIe HotPlug no longer unloads radeon. For this >>> bugzilla report we can close it. >>> >>> #2) This still has weird results however, radeon.hard_reset=1 is experimental >>> and while it attempts to reset GPU, PCIe HotPlug seems to interact in this. >>> >>> This can be tested by adding to grub command line radeon.hard_reset=1. >>> When X has started up, trigger a reset by cat >>> /sys/kernel/debug/dri/#/radeon_gpu_reset. It will output 0, cat it again will >>> show 1. >>> >>> Attempt to drag a window. The this will trigger a GPU reset, but fail to >>> recover, its unknown if PCIe HotPlug is preventing a proper reset or not but >>> there is pciehp calls in the stack trace. >> >> A PCIe device reset usually looks like a hotplug event because the >> PCIe link goes down and comes back up. As far as the PCI core is >> concerned, it can't tell the difference between (1) a simple reset >> where the link bounces and (2) removal of one device followed by >> addition of another. >> >> b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events >> for a device") addressed this for some similar cases, but it looks >> like we probably need some more calls to pci_ignore_hotplug() in the >> radeon driver reset methods. >> >> Can you please open a bugzilla and attach the complete dmesg log, >> including the GPU reset and recovery failure? > > Is there a way we could temporarily disable pci hotplug around a GPU reset? There is pci_ignore_hotplug(). Do you mean something more? Oh, I guess you mean a way to disable, then *re*-enable hotplug. We can easily add that if that would help. Bjorn -- 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
