On Tue, 1 Aug 2023 03:14:27 +0300
Dmitry Osipenko <dmitry.osipe...@collabora.com> wrote:
> Panfrost IRQ handler may stuck for a long time, for example this happens
> when there is a bad HDMI connection and HDMI handler takes a long time to
> finish processing, holding Panfrost. Make Panfrost's job timeout handler
> to sync IRQ before checking fence signal status in order to prevent
> spurious job timeouts due to a slow IRQ processing.
>
> Reviewed-by: Steven Price <steven.pr...@arm.com>
> Reviewed-by: AngeloGioacchino Del Regno
> <angelogioacchino.delre...@collabora.com>
> Tested-by: AngeloGioacchino Del Regno
> <angelogioacchino.delre...@collabora.com> # MediaTek MT8192 and MT8195
> Chromebooks:
> Signed-off-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezil...@collabora.com>
Just a couple nits below.
> ---
>
> Changelog:
>
> v3: - Added comment to the code as was suggested by Boris
>
> - Added r-b/t-b from Steven and Angelo
>
> v2: - Moved synchronize_irq() after first signal-check to avoid unnecessary
> blocking on syncing.
>
> - Added warn message about high interrupt latency.
>
> drivers/gpu/drm/panfrost/panfrost_job.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c
> b/drivers/gpu/drm/panfrost/panfrost_job.c
> index dbc597ab46fb..ea1149354f9d 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -720,6 +720,21 @@ static enum drm_gpu_sched_stat
> panfrost_job_timedout(struct drm_sched_job
> if (dma_fence_is_signaled(job->done_fence))
> return DRM_GPU_SCHED_STAT_NOMINAL;
>
> + /*
> + * Panfrost IRQ handler may take long time to process if there is
^ may take a long time to process an
interrupt if there is ...
> + * another IRQ handler hogging the processing. For example, HDMI
> + * may stuck in IRQ handler for a significant time in a case of bad
For example, the HDMI encoder driver might be stuck in the IRQ
handler ...
> + * cable connection. In order to catch such cases and not report
> + * spurious Panfrost job timeouts, synchronize the IRQ handler and
> + * re-check the fence status.
> + */
> + synchronize_irq(pfdev->js->irq);
> +
> + if (dma_fence_is_signaled(job->done_fence)) {
> + dev_warn(pfdev->dev, "unexpectedly high interrupt latency\n");
> + return DRM_GPU_SCHED_STAT_NOMINAL;
> + }
> +
> dev_err(pfdev->dev, "gpu sched timeout, js=%d, config=0x%x,
> status=0x%x, head=0x%x, tail=0x%x, sched_job=%p",
> js,
> job_read(pfdev, JS_CONFIG(js)),
