From: Jordan Crouse <jcrouse@codeaurora.org>
To: Rob Clark <robdclark@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>,
Amit Pundir <amit.pundir@linaro.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Sharat Masetty <smasetty@codeaurora.org>,
lkml <linux-kernel@vger.kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
dri-devel@freedesktop.org,
freedreno <freedreno@lists.freedesktop.org>,
Sumit Semwal <sumit.semwal@linaro.org>
Subject: Re: [Freedreno] [PATCH v2 2/3] drm: msm: a6xx: Add support for A618
Date: Tue, 4 Feb 2020 09:34:51 -0700 [thread overview]
Message-ID: <20200204163451.GA14568@jcrouse1-lnx.qualcomm.com> (raw)
In-Reply-To: <CAF6AEGtxtJU5dJxd4idQgPL2HYgiLm2vJejjK-gzDXqtoaTr9w@mail.gmail.com>
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@linaro.org> wrote:
> >
> > On Wed, Jan 22, 2020 at 11:19 PM Sharat Masetty <smasetty@codeaurora.org> 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@codeaurora.org>
> > > ---
> > > 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@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/freedreno
> _______________________________________________
> Freedreno mailing list
> Freedreno@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/freedreno
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2020-02-04 16:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 7:19 [PATCH v2 1/3] drm: msm: Add 618 gpu to the adreno gpu list Sharat Masetty
2020-01-23 7:19 ` [PATCH v2 2/3] drm: msm: a6xx: Add support for A618 Sharat Masetty
2020-02-04 0:21 ` John Stultz
2020-02-04 0:40 ` [Freedreno] " Rob Clark
2020-02-04 16:34 ` Jordan Crouse [this message]
2020-01-23 7:19 ` [PATCH v2 3/3] drm: msm: a6xx: Dump GBIF registers, debugbus in gpu state Sharat Masetty
2020-01-23 15:58 ` [PATCH v2 1/3] drm: msm: Add 618 gpu to the adreno gpu list Jordan Crouse
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