From: Brian Norris briannorris@chromium.org
stable inclusion from stable-v5.10.122 commit fa0d3d71dc081377d7c56fa96f75401679834d7e category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5W6OE
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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@oss.nxp.com Cc: stable@vger.kernel.org Fixes: 1452c25b0e60 ("drm: Add helpers to kick off self refresh mode in drivers") Signed-off-by: Brian Norris briannorris@chromium.org Reviewed-by: Sean Paul seanpaul@chromium.org Signed-off-by: Douglas Anderson dianders@chromium.org Link: https://patchwork.freedesktop.org/patch/msgid/20220228122522.v2.2.Ic15a2ef69... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- drivers/gpu/drm/drm_atomic_helper.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 8a871e5c3e26..7fc8e7000046 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -996,9 +996,19 @@ crtc_needs_disable(struct drm_crtc_state *old_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->enable) ||