This is a note to let you know that I've just added the patch titled
drm/atomic: Force bridge self-refresh-exit on CRTC switch
to the 5.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-atomic-force-bridge-self-refresh-exit-on-crtc-switch.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e54a4424925a27ed94dff046db3ce5caf4b1e748 Mon Sep 17 00:00:00 2001
From: Brian Norris <briannorris@xxxxxxxxxxxx>
Date: Mon, 28 Feb 2022 12:25:32 -0800
Subject: drm/atomic: Force bridge self-refresh-exit on CRTC switch
From: Brian Norris <briannorris@xxxxxxxxxxxx>
commit e54a4424925a27ed94dff046db3ce5caf4b1e748 upstream.
It's possible to change which CRTC is in use for a given
connector/encoder/bridge while we're in self-refresh without fully
disabling the connector/encoder/bridge along the way. This can confuse
the bridge encoder/bridge, because
(a) it needs to track the SR state (trying to perform "active"
operations while the panel is still in SR can be Bad(TM)); and
(b) it tracks the SR state via the CRTC state (and after the switch, the
previous SR state is lost).
Thus, we need to either somehow carry the self-refresh state over to the
new CRTC, or else force an encoder/bridge self-refresh transition during
such a switch.
I choose the latter, so we disable the encoder (and exit PSR) before
attaching it to the new CRTC (where we can continue to assume a clean
(non-self-refresh) state).
This fixes PSR issues seen on Rockchip RK3399 systems with
drivers/gpu/drm/bridge/analogix/analogix_dp_core.c.
Change in v2:
- Drop "->enable" condition; this could possibly be "->active" to
reflect the intended hardware state, but it also is a little
over-specific. We want to make a transition through "disabled" any
time we're exiting PSR at the same time as a CRTC switch.
(Thanks Liu Ying)
Cc: Liu Ying <victor.liu@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 1452c25b0e60 ("drm: Add helpers to kick off self refresh mode in drivers")
Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
Reviewed-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220228122522.v2.2.Ic15a2ef69c540aee8732703103e2cff51fb9c399@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_atomic_helper.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1011,9 +1011,19 @@ crtc_needs_disable(struct drm_crtc_state
return drm_atomic_crtc_effectively_active(old_state);
/*
- * We need to run through the crtc_funcs->disable() function if the CRTC
- * is currently on, if it's transitioning to self refresh mode, or if
- * it's in self refresh mode and needs to be fully disabled.
+ * We need to disable bridge(s) and CRTC if we're transitioning out of
+ * self-refresh and changing CRTCs at the same time, because the
+ * bridge tracks self-refresh status via CRTC state.
+ */
+ if (old_state->self_refresh_active &&
+ old_state->crtc != new_state->crtc)
+ return true;
+
+ /*
+ * We also need to run through the crtc_funcs->disable() function if
+ * the CRTC is currently on, if it's transitioning to self refresh
+ * mode, or if it's in self refresh mode and needs to be fully
+ * disabled.
*/
return old_state->active ||
(old_state->self_refresh_active && !new_state->active) ||
Patches currently in stable-queue which might be from briannorris@xxxxxxxxxxxx are
queue-5.17/drm-atomic-force-bridge-self-refresh-exit-on-crtc-switch.patch
queue-5.17/drm-bridge-analogix_dp-support-psr-exit-to-disable-transition.patch
