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drm/gud: Don't retry a failed framebuffer flush
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If a framebuffer flush fails the driver will do one retry by requeing the
worker. Currently the worker is used even for synchronous flushing, but a
later patch will inline it, so this needs to change. Thinking about how to
solve this I came to the conclusion that this retry mechanism was a fix
for a problem that was only in the mind of the developer (me) and not
something that solved a real problem.

So let's remove this for now and revisit later should it become necessary.
gud_add_damage() has now only one caller so it can be inlined.

Reviewed-by: Javier Martinez Canillas <[email protected]>
Reviewed-by: Thomas Zimmermann <[email protected]>
Signed-off-by: Noralf Trønnes <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
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notro committed Dec 6, 2022
1 parent 951df98 commit f531d19
Showing 1 changed file with 8 additions and 40 deletions.
48 changes: 8 additions & 40 deletions drivers/gpu/drm/gud/gud_pipe.c
Original file line number Diff line number Diff line change
Expand Up @@ -333,37 +333,6 @@ void gud_clear_damage(struct gud_device *gdrm)
gdrm->damage.y2 = 0;
}

static void gud_add_damage(struct gud_device *gdrm, struct drm_rect *damage)
{
gdrm->damage.x1 = min(gdrm->damage.x1, damage->x1);
gdrm->damage.y1 = min(gdrm->damage.y1, damage->y1);
gdrm->damage.x2 = max(gdrm->damage.x2, damage->x2);
gdrm->damage.y2 = max(gdrm->damage.y2, damage->y2);
}

static void gud_retry_failed_flush(struct gud_device *gdrm, struct drm_framebuffer *fb,
struct drm_rect *damage)
{
/*
* pipe_update waits for the worker when the display mode is going to change.
* This ensures that the width and height is still the same making it safe to
* add back the damage.
*/

mutex_lock(&gdrm->damage_lock);
if (!gdrm->fb) {
drm_framebuffer_get(fb);
gdrm->fb = fb;
}
gud_add_damage(gdrm, damage);
mutex_unlock(&gdrm->damage_lock);

/* Retry only once to avoid a possible storm in case of continues errors. */
if (!gdrm->prev_flush_failed)
queue_work(system_long_wq, &gdrm->work);
gdrm->prev_flush_failed = true;
}

void gud_flush_work(struct work_struct *work)
{
struct gud_device *gdrm = container_of(work, struct gud_device, work);
Expand Down Expand Up @@ -407,14 +376,10 @@ void gud_flush_work(struct work_struct *work)
ret = gud_flush_rect(gdrm, fb, format, &rect);
if (ret) {
if (ret != -ENODEV && ret != -ECONNRESET &&
ret != -ESHUTDOWN && ret != -EPROTO) {
bool prev_flush_failed = gdrm->prev_flush_failed;

gud_retry_failed_flush(gdrm, fb, &damage);
if (!prev_flush_failed)
dev_err_ratelimited(fb->dev->dev,
"Failed to flush framebuffer: error=%d\n", ret);
}
ret != -ESHUTDOWN && ret != -EPROTO)
dev_err_ratelimited(fb->dev->dev,
"Failed to flush framebuffer: error=%d\n", ret);
gdrm->prev_flush_failed = true;
break;
}

Expand All @@ -439,7 +404,10 @@ static void gud_fb_queue_damage(struct gud_device *gdrm, struct drm_framebuffer
gdrm->fb = fb;
}

gud_add_damage(gdrm, damage);
gdrm->damage.x1 = min(gdrm->damage.x1, damage->x1);
gdrm->damage.y1 = min(gdrm->damage.y1, damage->y1);
gdrm->damage.x2 = max(gdrm->damage.x2, damage->x2);
gdrm->damage.y2 = max(gdrm->damage.y2, damage->y2);

mutex_unlock(&gdrm->damage_lock);

Expand Down

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