The mdp5 drm/kms driver currently does not work on command-mode DSI
panels due to 'vblank wait timed out' errors. This causes a latency
of seconds, or tens of seconds in some cases, before content is shown
on the panel. This hardware does not have the something that we can use
as a frame counter available when running in command mode, so we need to
fall back to using timestamps by setting the max_vblank_count to zero.
This can be done on a per-CRTC basis, so the convert mdp5 to use
drm_crtc_set_max_vblank_count().
This change was tested on a LG Nexus 5 (hammerhead) phone.
Signed-off-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
Suggested-by: Jeffrey Hugo <jeffrey.l.hugo@xxxxxxxxx>
---
drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c | 16 +++++++++++++++-
drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 2 +-
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
index c3751c95b452..6fde1097844f 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
@@ -450,6 +450,18 @@ static void mdp5_crtc_atomic_disable(struct drm_crtc *crtc,
mdp5_crtc->enabled = false;
}
+static void mdp5_crtc_vblank_on(struct drm_crtc *crtc)
+{
+ struct mdp5_crtc_state *mdp5_cstate = to_mdp5_crtc_state(crtc->state);
+ struct mdp5_interface *intf = mdp5_cstate->pipeline.intf;
+ u32 count;
+
+ count = intf->mode == MDP5_INTF_DSI_MODE_COMMAND ? 0 : 0xffffffff;
+ drm_crtc_set_max_vblank_count(crtc, count);
+
+ drm_crtc_vblank_on(crtc);
+}
+
static void mdp5_crtc_atomic_enable(struct drm_crtc *crtc,
struct drm_crtc_state *old_state)
{
@@ -486,7 +498,7 @@ static void mdp5_crtc_atomic_enable(struct drm_crtc *crtc,
}
/* Restore vblank irq handling after power is enabled */
- drm_crtc_vblank_on(crtc);
+ mdp5_crtc_vblank_on(crtc);
mdp5_crtc_mode_set_nofb(crtc);
@@ -1039,6 +1051,8 @@ static void mdp5_crtc_reset(struct drm_crtc *crtc)
mdp5_crtc_destroy_state(crtc, crtc->state);
__drm_atomic_helper_crtc_reset(crtc, &mdp5_cstate->base);
+
+ drm_crtc_vblank_reset(crtc);
}
static const struct drm_crtc_funcs mdp5_crtc_funcs = {
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
index 97179bec8902..fcb0b0455abe 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
@@ -750,7 +750,7 @@ struct msm_kms *mdp5_kms_init(struct drm_device *dev)
dev->driver->get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos;
dev->driver->get_scanout_position = mdp5_get_scanoutpos;
dev->driver->get_vblank_counter = mdp5_get_vblank_counter;
- dev->max_vblank_count = 0xffffffff;
+ dev->max_vblank_count = 0; /* max_vblank_count is set on each CRTC */
dev->vblank_disable_immediate = true;
return kms;
--
2.20.1
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