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From: Alexandre Courbot <gnurou@gmail.com>
To: Diego Viola <diego.viola@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dri-devel@lists.freedesktop.org, nouveau@spliet.org
Subject: Re: [PATCH v2] drm/nouveau/pmu: fix timeout on GP108
Date: Wed, 17 Feb 2021 12:30:30 +0900	[thread overview]
Message-ID: <CAAVeFuLLw+pb-vvxPbbgDGGLo4Vi-ReJAh_YH-3xUZEDyhDb-Q@mail.gmail.com> (raw)
In-Reply-To: <20210216161924.1687-1-diego.viola@gmail.com>

On Wed, Feb 17, 2021 at 1:20 AM Diego Viola <diego.viola@gmail.com> wrote:
>
> This code times out on GP108, probably because the BIOS puts it into a
> bad state.
>
> Since we reset the PMU on driver load anyway, we are at no risk from
> missing a response from it since we are not waiting for one to begin
> with.

This looks safe to me, provided indeed that the PMU's reset is not
called outside of initialization (which for GP108 is shouldn't be
IIRC?).

>
> Signed-off-by: Diego Viola <diego.viola@gmail.com>
> ---
>  drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> index a0fe607c9c07..5c802f2d00cb 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> @@ -102,12 +102,8 @@ nvkm_pmu_reset(struct nvkm_pmu *pmu)
>         if (!pmu->func->enabled(pmu))
>                 return 0;
>
> -       /* Inhibit interrupts, and wait for idle. */
> +       /* Inhibit interrupts. */
>         nvkm_wr32(device, 0x10a014, 0x0000ffff);
> -       nvkm_msec(device, 2000,
> -               if (!nvkm_rd32(device, 0x10a04c))
> -                       break;
> -       );
>
>         /* Reset. */
>         if (pmu->func->reset)
> --
> 2.30.1
>

WARNING: multiple messages have this Message-ID (diff)
From: Alexandre Courbot <gnurou@gmail.com>
To: Diego Viola <diego.viola@gmail.com>
Cc: nouveau@spliet.org, Ben Skeggs <bskeggs@redhat.com>,
	dri-devel@lists.freedesktop.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] drm/nouveau/pmu: fix timeout on GP108
Date: Wed, 17 Feb 2021 12:30:30 +0900	[thread overview]
Message-ID: <CAAVeFuLLw+pb-vvxPbbgDGGLo4Vi-ReJAh_YH-3xUZEDyhDb-Q@mail.gmail.com> (raw)
In-Reply-To: <20210216161924.1687-1-diego.viola@gmail.com>

On Wed, Feb 17, 2021 at 1:20 AM Diego Viola <diego.viola@gmail.com> wrote:
>
> This code times out on GP108, probably because the BIOS puts it into a
> bad state.
>
> Since we reset the PMU on driver load anyway, we are at no risk from
> missing a response from it since we are not waiting for one to begin
> with.

This looks safe to me, provided indeed that the PMU's reset is not
called outside of initialization (which for GP108 is shouldn't be
IIRC?).

>
> Signed-off-by: Diego Viola <diego.viola@gmail.com>
> ---
>  drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> index a0fe607c9c07..5c802f2d00cb 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> @@ -102,12 +102,8 @@ nvkm_pmu_reset(struct nvkm_pmu *pmu)
>         if (!pmu->func->enabled(pmu))
>                 return 0;
>
> -       /* Inhibit interrupts, and wait for idle. */
> +       /* Inhibit interrupts. */
>         nvkm_wr32(device, 0x10a014, 0x0000ffff);
> -       nvkm_msec(device, 2000,
> -               if (!nvkm_rd32(device, 0x10a04c))
> -                       break;
> -       );
>
>         /* Reset. */
>         if (pmu->func->reset)
> --
> 2.30.1
>
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  reply	other threads:[~2021-02-17  3:31 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-16 16:19 [PATCH v2] drm/nouveau/pmu: fix timeout on GP108 Diego Viola
2021-02-16 16:19 ` Diego Viola
2021-02-17  3:30 ` Alexandre Courbot [this message]
2021-02-17  3:30   ` Alexandre Courbot
2021-02-24  9:50   ` Ben Skeggs
2021-02-24  9:50     ` Ben Skeggs
2021-02-25  4:04     ` Diego Viola
2021-02-25  4:04       ` Diego Viola
2021-02-25  5:22     ` Diego Viola
2021-02-25  5:22       ` Diego Viola
2021-02-25  5:37       ` Diego Viola
2021-02-25  5:37         ` Diego Viola

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