[PATCH v2 1/5] drm/etnaviv: hold GPU lock across perfmon sampling

[Christian Gmeiner]

>
> The perfmon sampling mutates shared GPU state (e.g. VIVS_HI_CLOCK_CONTROL
> to select the pipe for the perf counter reads). To avoid clashing with
> other functions mutating the same state (e.g. etnaviv_gpu_update_clock)
> the perfmon sampling needs to hold the GPU lock.
>
> Fixes: 68dc0b295dcb ("drm/etnaviv: use 'sync points' for performance monitor requests")
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>

Reviewed-by: Christian Gmeiner <cgmeiner at igalia.com>

> ---
> v2: new patch
> ---
>  drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> index 7c7f97793ddd..2bd14d3501e2 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> @@ -1330,6 +1330,8 @@ static void sync_point_perfmon_sample_pre(struct etnaviv_gpu *gpu,
>  {
>         u32 val;
>
> +       mutex_lock(&gpu->lock);
> +
>         /* disable clock gating */
>         val = gpu_read_power(gpu, VIVS_PM_POWER_CONTROLS);
>         val &= ~VIVS_PM_POWER_CONTROLS_ENABLE_MODULE_CLOCK_GATING;
> @@ -1341,6 +1343,8 @@ static void sync_point_perfmon_sample_pre(struct etnaviv_gpu *gpu,
>         gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, val);
>
>         sync_point_perfmon_sample(gpu, event, ETNA_PM_PROCESS_PRE);
> +
> +       mutex_unlock(&gpu->lock);
>  }
>
>  static void sync_point_perfmon_sample_post(struct etnaviv_gpu *gpu,
> @@ -1350,13 +1354,9 @@ static void sync_point_perfmon_sample_post(struct etnaviv_gpu *gpu,
>         unsigned int i;
>         u32 val;
>
> -       sync_point_perfmon_sample(gpu, event, ETNA_PM_PROCESS_POST);
> -
> -       for (i = 0; i < submit->nr_pmrs; i++) {
> -               const struct etnaviv_perfmon_request *pmr = submit->pmrs + i;
> +       mutex_lock(&gpu->lock);
>
> -               *pmr->bo_vma = pmr->sequence;
> -       }
> +       sync_point_perfmon_sample(gpu, event, ETNA_PM_PROCESS_POST);
>
>         /* disable debug register */
>         val = gpu_read(gpu, VIVS_HI_CLOCK_CONTROL);
> @@ -1367,6 +1367,14 @@ static void sync_point_perfmon_sample_post(struct etnaviv_gpu *gpu,
>         val = gpu_read_power(gpu, VIVS_PM_POWER_CONTROLS);
>         val |= VIVS_PM_POWER_CONTROLS_ENABLE_MODULE_CLOCK_GATING;
>         gpu_write_power(gpu, VIVS_PM_POWER_CONTROLS, val);
> +
> +       mutex_unlock(&gpu->lock);
> +
> +       for (i = 0; i < submit->nr_pmrs; i++) {
> +               const struct etnaviv_perfmon_request *pmr = submit->pmrs + i;
> +
> +               *pmr->bo_vma = pmr->sequence;
> +       }

-- 
greets
--
Christian Gmeiner, MSc

https://christian-gmeiner.info/privacypolicy