| Message ID | be610a7596ad8fee7da092161888c532c2eb2908.1512411775.git.guillaume.tucker@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/12/17 18:37, Guillaume Tucker wrote: > If the firmware fails to load then ->fini() will be called before the > device has been initialised, causing the kernel to hang while trying > to write to a register. Add a test in ->fini() to avoid this issue. > > This fixes a kernel hang on tegra124. > > Fixes: b17de35a2ebbe ("drm/nouveau/bar: implement bar1 teardown") > Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com> > CC: Ben Skeggs <bskeggs@redhat.com> > --- > drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c > index a3ba7f50198b..95e2aba64aad 100644 > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c > @@ -43,9 +43,12 @@ gf100_bar_bar1_wait(struct nvkm_bar *base) > } > > void > -gf100_bar_bar1_fini(struct nvkm_bar *bar) > +gf100_bar_bar1_fini(struct nvkm_bar *base) > { > - nvkm_mask(bar->subdev.device, 0x001704, 0x80000000, 0x00000000); > + struct nvkm_device *device = base->subdev.device; > + > + if (base->subdev.oneinit) > + nvkm_mask(device, 0x001704, 0x80000000, 0x00000000); > } > > void I have tested this and it works for me. Thanks for fixing this! Would be good to get Ben's ACK, but you can have my ... Tested-by: Jon Hunter <jonathanh@nvidia.com> Cheers Jon
On 05/12/17 18:32, Ben Skeggs wrote: > On Wed, Dec 6, 2017 at 12:30 AM, Jon Hunter <jonathanh@nvidia.com> wrote: > >> >> On 04/12/17 18:37, Guillaume Tucker wrote: >>> If the firmware fails to load then ->fini() will be called before the >>> device has been initialised, causing the kernel to hang while trying >>> to write to a register. Add a test in ->fini() to avoid this issue. >>> >>> This fixes a kernel hang on tegra124. >>> >>> Fixes: b17de35a2ebbe ("drm/nouveau/bar: implement bar1 teardown") >>> Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com> >>> CC: Ben Skeggs <bskeggs@redhat.com> >>> --- >>> drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c | 7 +++++-- >>> 1 file changed, 5 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >> b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>> index a3ba7f50198b..95e2aba64aad 100644 >>> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>> @@ -43,9 +43,12 @@ gf100_bar_bar1_wait(struct nvkm_bar *base) >>> } >>> >>> void >>> -gf100_bar_bar1_fini(struct nvkm_bar *bar) >>> +gf100_bar_bar1_fini(struct nvkm_bar *base) >>> { >>> - nvkm_mask(bar->subdev.device, 0x001704, 0x80000000, 0x00000000); >>> + struct nvkm_device *device = base->subdev.device; >>> + >>> + if (base->subdev.oneinit) >>> + nvkm_mask(device, 0x001704, 0x80000000, 0x00000000); >>> } >>> >>> void >> >> I have tested this and it works for me. Thanks for fixing this! Would be >> good to get Ben's ACK, but you can have my ... >> > I'd love to get a good explanation as to why it hangs without this change, > as, on the surface, it's not immediately obvious as to why it's hanging. To be fair I'm not entirely sure either why this causes a hang, I haven't read the TRM... The iomem has been mapped at this point, so accessing the register should work. One clue is when you look at _bar1_init(), the 0x1704 register is initialised with some (device instance?) memory address. So it's possible that the hardware does something special when you set this to 0 as in _bar1_fini(), which may fail in particular if it was previously not initialised with a valid address. This is merely guesswork, would be interested to find out the real explanation though. >> Tested-by: Jon Hunter <jonathanh@nvidia.com> Thanks! Guillaume
On 06/12/17 09:22, Guillaume Tucker wrote: > On 05/12/17 18:32, Ben Skeggs wrote: >> On Wed, Dec 6, 2017 at 12:30 AM, Jon Hunter <jonathanh@nvidia.com> wrote: >> >>> >>> On 04/12/17 18:37, Guillaume Tucker wrote: >>>> If the firmware fails to load then ->fini() will be called before the >>>> device has been initialised, causing the kernel to hang while trying >>>> to write to a register. Add a test in ->fini() to avoid this issue. >>>> >>>> This fixes a kernel hang on tegra124. >>>> >>>> Fixes: b17de35a2ebbe ("drm/nouveau/bar: implement bar1 teardown") >>>> Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com> >>>> CC: Ben Skeggs <bskeggs@redhat.com> >>>> --- >>>> drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c | 7 +++++-- >>>> 1 file changed, 5 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>> b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>>> index a3ba7f50198b..95e2aba64aad 100644 >>>> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>>> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c >>>> @@ -43,9 +43,12 @@ gf100_bar_bar1_wait(struct nvkm_bar *base) >>>> } >>>> >>>> void >>>> -gf100_bar_bar1_fini(struct nvkm_bar *bar) >>>> +gf100_bar_bar1_fini(struct nvkm_bar *base) >>>> { >>>> - nvkm_mask(bar->subdev.device, 0x001704, 0x80000000, 0x00000000); >>>> + struct nvkm_device *device = base->subdev.device; >>>> + >>>> + if (base->subdev.oneinit) >>>> + nvkm_mask(device, 0x001704, 0x80000000, 0x00000000); >>>> } >>>> >>>> void >>> >>> I have tested this and it works for me. Thanks for fixing this! Would be >>> good to get Ben's ACK, but you can have my ... >>> >> I'd love to get a good explanation as to why it hangs without this >> change, >> as, on the surface, it's not immediately obvious as to why it's hanging. > > To be fair I'm not entirely sure either why this causes a hang, I > haven't read the TRM... The iomem has been mapped at this point, > so accessing the register should work. One clue is when you look > at _bar1_init(), the 0x1704 register is initialised with > some (device instance?) memory address. So it's possible that > the hardware does something special when you set this to 0 as in > _bar1_fini(), which may fail in particular if it was previously > not initialised with a valid address. > > This is merely guesswork, would be interested to find out the > real explanation though. OK, well that's no good. It's a good pointer, but we need to make sure we understand the root of this hang. I will see if I have sometime to dig into this further, maybe next week. Cheers Jon
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c index a3ba7f50198b..95e2aba64aad 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c @@ -43,9 +43,12 @@ gf100_bar_bar1_wait(struct nvkm_bar *base) } void -gf100_bar_bar1_fini(struct nvkm_bar *bar) +gf100_bar_bar1_fini(struct nvkm_bar *base) { - nvkm_mask(bar->subdev.device, 0x001704, 0x80000000, 0x00000000); + struct nvkm_device *device = base->subdev.device; + + if (base->subdev.oneinit) + nvkm_mask(device, 0x001704, 0x80000000, 0x00000000); } void
If the firmware fails to load then ->fini() will be called before the device has been initialised, causing the kernel to hang while trying to write to a register. Add a test in ->fini() to avoid this issue. This fixes a kernel hang on tegra124. Fixes: b17de35a2ebbe ("drm/nouveau/bar: implement bar1 teardown") Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com> CC: Ben Skeggs <bskeggs@redhat.com> --- drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)