[PATCH 1/3] drm/vkms: Reduce critical section

Maíra Canal mcanal at igalia.com
Mon May 15 13:52:03 UTC 2023


The spinlock composer_lock protects the variables crc_pending,
wb_pending, frame_start and frame_end, which are variables that are used
by the composer worker. There is no need to protect the wb_frame_info
information with a spinlock. Therefore, reduce the critical section of
the lock by removing the assignments to the wb_frame_info from the
critical section.

Signed-off-by: Maíra Canal <mcanal at igalia.com>
---
 drivers/gpu/drm/vkms/vkms_writeback.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
index 84a51cd281b9..9a126f678d73 100644
--- a/drivers/gpu/drm/vkms/vkms_writeback.c
+++ b/drivers/gpu/drm/vkms/vkms_writeback.c
@@ -142,11 +142,13 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn,
 
 	spin_lock_irq(&output->composer_lock);
 	crtc_state->active_writeback = active_wb;
+	crtc_state->wb_pending = true;
+	spin_unlock_irq(&output->composer_lock);
+
 	wb_frame_info->offset = fb->offsets[0];
 	wb_frame_info->pitch = fb->pitches[0];
 	wb_frame_info->cpp = fb->format->cpp[0];
-	crtc_state->wb_pending = true;
-	spin_unlock_irq(&output->composer_lock);
+
 	drm_writeback_queue_job(wb_conn, connector_state);
 	active_wb->wb_write = get_line_to_frame_function(wb_format);
 	drm_rect_init(&wb_frame_info->src, 0, 0, crtc_width, crtc_height);
-- 
2.40.1



More information about the dri-devel mailing list