On 31-Jan-20 4:50 PM, Ville Syrjälä wrote:
On Thu, Jan 30, 2020 at 08:07:07PM +0000, Souza, Jose wrote:
On Thu, 2020-01-30 at 19:25 +0200, Ville Syrjälä wrote:
On Thu, Jan 16, 2020 at 05:58:37PM -0800, José Roberto de Souza
wrote:
TGL timeouts when disabling MST transcoder and fifo underruns over
MST
transcoders are fixed when setting TRANS_DDI_MODE_SELECT to 0(HDMI
mode) during the disable sequence.
Although BSpec disable sequence don't require this step it is a
harmless change and it is also done by Windows driver.
Anyhow HW team was notified about that but it can take some time to
documentation to be updated.
A case that always lead to those issues is:
- do a modeset enabling pipe A and pipe B in the same MST stream
leaving A as master
- disable pipe A, promote B as master doing a full modeset in A
- enable pipe A, changing the master transcoder back to A(doing a
full modeset in B)
- Pow: underruns and timeouts
The transcoders involved will only work again when complete
disabled
and their power wells turned off causing a reset in their
registers.
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_ddi.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
b/drivers/gpu/drm/i915/display/intel_ddi.c
index 32ea3c7e8b62..82e90f271974 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -1997,6 +1997,7 @@ void intel_ddi_disable_transcoder_func(const
struct intel_crtc_state *crtc_state
val = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
val &= ~TRANS_DDI_FUNC_ENABLE;
+ val &= ~TRANS_DDI_MODE_SELECT_MASK;
Feels a bit early since IIRC we still leave a bunch of other stuff
enabled/selected here. In fact we don't seem to be clearing the DDI
select
anywhere at all? That one I would be more suspicious of than the
mode.
But maybe we should just clear both somewhere? I would suggest it
should
be when we clear the port select finally.
We are clearing DDI select, in our code it is named as
TGL_TRANS_DDI_PORT_MASK/TRANS_DDI_PORT_MASK.
For TGL in MST mode we clear DDI select in the block below for MST
slaves and then in intel_ddi_post_disable_dp() for MST master as
instructed by Display port sequences.
Ah. Hmm, so that can't be it then. Bummer. I guess I would still feel
a bit safer if we clear the mode select alongside the the DDI select
for the master. Since the spec says the DDI select must remain set for
the master there must be something still going on, and so I worry that
something might not work quite right if we change the mode
prematurely.
Hi Ville/Jose,
We are still observing
=>*ERROR* Timed out waiting for ACT sent when disabling
=>FIFO underruns
Do we need a change disable sequence?
if (INTEL_GEN(dev_priv) >= 12) {
if (!intel_dp_mst_is_master_trans(crtc_state))
--
2.25.0
--
~Swati Sharma
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