On 2013.07.30 at 20:46 +0200, Markus Trippelsdorf wrote: > On 2013.07.30 at 10:53 -0400, Alex Deucher wrote: > > On Tue, Jul 30, 2013 at 7:27 AM, Markus Trippelsdorf > > <markus@xxxxxxxxxxxxxxx> wrote: > > > On 2013.07.29 at 15:53 -0400, Alex Deucher wrote: > > >> On Mon, Jul 29, 2013 at 2:10 PM, Eric W. Biederman > > >> <ebiederm@xxxxxxxxxxxx> wrote: > > >> > Alex Deucher <alexdeucher@xxxxxxxxx> writes: > > >> > > > >> >> On Mon, Jul 29, 2013 at 11:50 AM, Eric W. Biederman > > >> >> <ebiederm@xxxxxxxxxxxx> wrote: > > >> >>> > > >> >>> > > >> >>> Alex Deucher <alexdeucher@xxxxxxxxx> wrote: > > >> >>>>On Mon, Jul 29, 2013 at 10:09 AM, Markus Trippelsdorf > > >> >>>><markus@xxxxxxxxxxxxxxx> wrote: > > >> >>>>> On 2013.07.29 at 09:58 -0400, Alex Deucher wrote: > > >> >>>>>> On Mon, Jul 29, 2013 at 3:51 AM, Markus Trippelsdorf > > >> >>>>>> <markus@xxxxxxxxxxxxxxx> wrote: > > >> >>>>>> > On my test machine Xorg doesn't start anymore when I kexec into a > > >> >>>>>> > 3.11.0-rc3 kernel. > > >> >>>>>> > > >> >>>>>> With kexec, dpm doesn't get torn down properly which can result in a > > >> >>>>>> bad hardware state when the driver loads again. Does the attached > > >> >>>>>> patch help? It attempts to disable dpm at startup in case it wasn't > > >> >>>>>> torn down properly previously. > > >> >>>>> > > >> >>>>> dpm initialization now works, but unfortunately GPU acceleration > > >> >>>>still gets > > >> >>>>> disabled: > > >> >>>> > > >> >>>>Stupid kexec complicates things. We need to make sure dpm is torn > > >> >>>>down before we init the rest of the GPU, but dpm needs get initialized > > >> >>>>later in the init process since it depends on certain other state from > > >> >>>>the driver. I need to think about this for a bit. I'm not sure of a > > >> >>>>good way to handle this. > > >> >>> > > >> >>> You might just want to implement a shutdown method that cleans things up properly. At least as a first pass until you worry about things like kexec on panic. > > >> >>> > > >> >>> Or can you not shutdown the graphics stack on reboot because of the need to display the kernels shutdown progress? > > >> >> > > >> >> Does kexec actually call this shutdown method? The driver implements > > >> >> appropriate clean-up measures if it's shutdown properly. > > >> > > > >> > Absoltuely. All parts of the reboot path call ->shutdown. Including > > >> > kexec. > > >> > > > >> > You don't get a device remove/hotunplug but unless this is a kexec on > > >> > panic ->shutdown is most definitely called. Now I am talking about the > > >> > device layer/pci layer shutdown method I don't know how gpu drivers are > > >> > wired up. GPU land was a little strange last I looked. Hopefully it > > >> > isn't so strange that there is a method named shutdown that is not wired > > >> > up. > > >> > > >> It doesn't look like the drm infrastructure has a shutdown callback. > > >> The drm drivers register a drm_driver callback struct that includes an > > >> unload callback which takes care of all the device teardown (if you > > >> unload the module for example). I don't know that it actually gets > > >> called at kexec time however. I don't know enough about how kexec > > >> works. > > > > > > BTW there is r100_restore_sanity() in drm/radeon/r100.c that explicitly > > > handles the kexec case during init. So maybe an r600_restore_sanity() > > > function is needed? > > > > > > (One of the advantages of using kexec (besides the much quicker boot > > > time) is that the monitor is not switched off and then on during boot. > > > I guess that advantage would be lost if the unload callback would be > > > called.) > > > > r100_restore_sanity() is basically a set of hacks (that gets called at > > driver startup) to work around the fact that with kexec the drm driver > > is not torn down correctly. So we could add a bunch more asic > > specific tear down sequences to deal with dpm (and all the other > > engines on the GPU that may potentially cause problems if they are not > > torn down properly), but that will just turn into a mess. All of > > these hacks also add latency to the driver load. I think the best > > solution would probably be to figure how to hook up the drm unload > > callback to the shutdown method that kexec uses. > > FYI the following (ugly) hack works for me. No. It still fails, although much more infrequently (~ on every 6-8 boot). I begin to wonder if: [drm:r600_dma_ring_test] *ERROR* radeon: ring 3 test failed (0xCAFEDEAD) is an simple initialization bug that doesn't directly depend on kexec at all. -- Markus _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
