[PATCH] drm/amdgpu/smu: add an update table lock

[Alex Deucher]

On Mon, Feb 17, 2020 at 10:01 PM Quan, Evan <Evan.Quan at amd.com> wrote:
>
> Hi Alex,
>
> Did you seen any issue caused by this?

Seems to help on:
https://gitlab.freedesktop.org/drm/amd/issues/1047
I haven't been able to prove to myself that the existing high level
locking covers every case.

Alex

>
> Regards,
> Evan
> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Alex Deucher
> Sent: Tuesday, February 18, 2020 5:38 AM
> To: amd-gfx at lists.freedesktop.org
> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>
> Subject: [PATCH] drm/amdgpu/smu: add an update table lock
>
> The driver uses a staging buffer to update tables in the SMU.
> Add a lock to make sure we don't try and do this concurrently
> by accident.
>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/powerplay/amdgpu_smu.c     | 7 ++++++-
>  drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h | 1 +
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
> index 9f2428fd98f6..437a3e7b36b4 100644
> --- a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
> +++ b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
> @@ -530,6 +530,7 @@ int smu_update_table(struct smu_context *smu, enum smu_table_id table_index, int
>
>         table_size = smu_table->tables[table_index].size;
>
> +       mutex_lock(&smu->update_table_lock);
>         if (drv2smu) {
>                 memcpy(table->cpu_addr, table_data, table_size);
>                 /*
> @@ -544,13 +545,16 @@ int smu_update_table(struct smu_context *smu, enum smu_table_id table_index, int
>                                           SMU_MSG_TransferTableSmu2Dram,
>                                           table_id | ((argument & 0xFFFF) << 16));
>         if (ret)
> -               return ret;
> +               goto unlock;
>
>         if (!drv2smu) {
>                 amdgpu_asic_flush_hdp(adev, NULL);
>                 memcpy(table_data, table->cpu_addr, table_size);
>         }
>
> +unlock:
> +       mutex_unlock(&smu->update_table_lock);
> +
>         return ret;
>  }
>
> @@ -900,6 +904,7 @@ static int smu_sw_init(void *handle)
>
>         mutex_init(&smu->sensor_lock);
>         mutex_init(&smu->metrics_lock);
> +       mutex_init(&smu->update_table_lock);
>
>         smu->watermarks_bitmap = 0;
>         smu->power_profile_mode = PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;
> diff --git a/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h b/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h
> index 97b6714e83e6..506288072e8e 100644
> --- a/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h
> +++ b/drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h
> @@ -362,6 +362,7 @@ struct smu_context
>         struct mutex                    mutex;
>         struct mutex                    sensor_lock;
>         struct mutex                    metrics_lock;
> +       struct mutex                    update_table_lock;
>         uint64_t pool_size;
>
>         struct smu_table_context        smu_table;
> --
> 2.24.1
>
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