On Mon, Feb 03, 2020 at 04:40:40PM -0800, Rob Clark wrote: > On Mon, Feb 3, 2020 at 4:21 PM John Stultz <john.stultz@xxxxxxxxxx> wrote: > > > > On Wed, Jan 22, 2020 at 11:19 PM Sharat Masetty <smasetty@xxxxxxxxxxxxxx> wrote: > > > > > > This patch adds support for enabling Graphics Bus Interface(GBIF) > > > used in multiple A6xx series chipets. Also makes changes to the > > > PDC/RSC sequencing specifically required for A618. This is needed > > > for proper interfacing with RPMH. > > > > > > Signed-off-by: Sharat Masetty <smasetty@xxxxxxxxxxxxxx> > > > --- > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > > index dc8ec2c..2ac9a51 100644 > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c > > > @@ -378,6 +378,18 @@ static int a6xx_hw_init(struct msm_gpu *gpu) > > > struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu); > > > int ret; > > > > > > + /* > > > + * During a previous slumber, GBIF halt is asserted to ensure > > > + * no further transaction can go through GPU before GPU > > > + * headswitch is turned off. > > > + * > > > + * This halt is deasserted once headswitch goes off but > > > + * incase headswitch doesn't goes off clear GBIF halt > > > + * here to ensure GPU wake-up doesn't fail because of > > > + * halted GPU transactions. > > > + */ > > > + gpu_write(gpu, REG_A6XX_GBIF_HALT, 0x0); > > > + > > > /* Make sure the GMU keeps the GPU on while we set it up */ > > > a6xx_gmu_set_oob(&a6xx_gpu->gmu, GMU_OOB_GPU_SET); > > > > > > > So I already brought this up on #freedreno but figured I'd follow up > > on the list. > > > > With linus/master, I'm seeing hard crashes (into usb crash mode) with > > the db845c, which I isolated down to this patch, and then to the chunk > > above. > > (repeating my speculation from #freedreno for benefit of those not on IRC) > > I'm suspecting, that like the registers to take the GPU out of secure > mode, this register is being blocked on LA devices (like db845c), > which is why we didn't see this on cheza. > > Maybe we can make this write conditional on whether we have a zap shader? Sorry, I was WFH yesterday and didn't have IRC on. The 845 doesn't have GBIF (it still uses VBIF) and on a AC enabled target large chunks of unused register space would be blocked by default so Rob's hypothesis is correct. Since the 845 is the only a6xx target that still has a VBIF a !adreno_is_a630() check would do here, but I'm not 100% convinced we need this code at all. We explicitly clear the GBIF halt in the stop function before the headswitch is turned off so I think this is mostly unneeded paranoia. I need to get a tree with the 618 code in it and I'll try to get a fix out shortly. Jordan > > Dropping the gpu_write line above gets things booting again for me. > > > > Let me know if there are any follow on patches I can help validate. > > > > thanks > > -john > > _______________________________________________ > > Freedreno mailing list > > Freedreno@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/freedreno > _______________________________________________ > Freedreno mailing list > Freedreno@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/freedreno -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
