Re: [PATCH v2] drm/msm/dp: enable widebus on all relevant chipsets

From: Abhinav Kumar
Date: Tue Jul 30 2024 - 19:50:28 EST




On 7/30/2024 4:34 PM, Dmitry Baryshkov wrote:
On Wed, 31 Jul 2024 at 01:27, Bjorn Andersson <quic_bjorande@xxxxxxxxxxx> wrote:

On Tue, Jul 30, 2024 at 11:58:19PM +0300, Dmitry Baryshkov wrote:
Hi Abhinav,

On Tue, 30 Jul 2024 at 22:50, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:

Hardware document indicates that widebus is recommended on DP on all
MDSS chipsets starting version 5.x.x and above.

Follow the guideline and mark widebus support on all relevant
chipsets for DP.

Fixes: 766f705204a0 ("drm/msm/dp: Remove now unused connector_type from desc")
Fixes: 1b2d98bdd7b7 ("drm/msm/dp: Add DisplayPort controller for SM8650")

The issues are present in the following commits. Please consider using
them instead:

Fixes: 757a2f36ab09 ("drm/msm/dp: enable widebus feature for display port")
Fixes: 1b2d98bdd7b7 ("drm/msm/dp: Add DisplayPort controller for SM8650")


But are we really fixing any bugs/issues here? While the docs do
recommend widebus, we're effectively enabling more harware/features.

Unless there's a strong reason (which I'm not confident that the commit
message entails), I think we should drop the fixes-tags and just bring
this to 6.12...

I'm fine either way. I'll check tomorrow if this is required to fix
https://gitlab.freedesktop.org/drm/msm/-/issues/43.


In v1, I also did not have the Fixes tag and I admit, originally even though I made the change in an attempt to fix another issue, it was not resolving the issue completely so there is no functional issue getting fixed due to the change.

I have confirmed that on my setup this patch is not needed to fix that bug.

I decided to add the Fixes tag in v2 because not following the hw doc recommendation is also a bug as it can lead to unexplained issues. Thats why I am still divided on this.

If the consensus is not to take it as a fix, I am fine with it and will not include it and while we are compiling the changes for 6.12 this can be included without the Fixes tags.