On 7/12/2024 4:11 PM, Dmitry Baryshkov wrote:
On Fri, 12 Jul 2024 at 22:41, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
On 6/24/2024 2:13 PM, Dmitry Baryshkov wrote:
The commit b954fa6baaca ("drm/msm/dpu: Refactor rm iterator") removed
zero-init of the hw_ctl array, but didn't change the error condition,
that checked for hw_ctl[i] being NULL. Use indices check instead.
Fixes: b954fa6baaca ("drm/msm/dpu: Refactor rm iterator")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 5d205e09cf45..7613005fbfea 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -1186,7 +1186,7 @@ static void :tag(struct drm_encoder *drm_enc,
return;
}
- if (!hw_ctl[i]) {
+ if (i >= num_ctl) {
This is not very clear to me.
How will we hit this condition? I dont see i going beyond 1 in this loop
and neither should num_ctl
Why? the driver doesn't support flushing through a single CTL, so
num_ctl = num_intf.
num_ctl will be = num_intf, but what I was trying to understand here is
that , previously this condition was making sure that we have a ctl
assigned for each physical encoder which is actually a requirement for
the display pipeline. If we assigned a hw_ctl for one phys encoder and
not the other, its an error.
But on closer look, I think even your check will catch that.
Will it be just easier to bring back the NULL assignment at the top?
struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_ENC] = { NULL };
I also see the same issue for other blocks such as hw_dsc, hw_lm
Other blocks loop properly up to the num_resource. I'd prefer to drop
the NULL init from the DSPP init and use num_dspp instead.
Overall, I think the purpose of NULL init was to make sure that before
we call to_dpu_hw_***() macros, we have a valid hw_*.
We could use either num_* or the hw_* as both are returned by RM.
One side-note here is with a proper NULL hw_ctl is that the consumers of
hw_ctl should also be able to check for NULL correctly.
So for example dpu_encoder_phys layers use if (!phys->hw_ctl) checks but
today we do not set phys->hw_ctl to NULL correctly.
Do you think that instead of the return statements, we should do
something like
dpu_enc->hw_ctl = i < num_ctl ?
to_dpu_hw_ctl(hw_ctl[i]) : NULL;
But this will need the NULL init back.
DPU_ERROR_ENC(dpu_enc,
"no ctl block assigned at idx: %d\n", i);
return;
