[PATCH 13/14] drm/msm/dp: move next_bridge handling to dp_display

[Dmitry Baryshkov]

On Tue, 23 Jan 2024 at 01:20, Kuogee Hsieh <quic_khsieh at quicinc.com> wrote:
>
>
> On 1/22/2024 9:28 AM, Kuogee Hsieh wrote:
> >
> > On 1/19/2024 6:31 PM, Dmitry Baryshkov wrote:
> >> On Fri, 19 Jan 2024 at 23:14, Kuogee Hsieh <quic_khsieh at quicinc.com>
> >> wrote:
> >>> Dmitry,
> >>>
> >>> I am testing this patch serial with msm-next branch.
> >>>
> >>> This patch cause system crash during booting up for me.
> >>>
> >>> Is this patch work for you?
> >> Yes, tested on top of linux-next. However I only tested it with
> >> DP-over-USBC. What is your testcase? Could you please share the crash
> >> log?
> >
> > I tested it on chrome device (sc7280) which has eDP as primary and
> > without external USBC DP connected.
> >
> > It crashes during boot.
> >
> > I will debug it more and collect logs for you.
> >
> Below  patch work for chrome with both eDP and external DP.
>
> We have to return failed if it is the external DP and return value of
> devm_drm_of_get_bridge()  is !ENODEV since DP does not have next bridge.
>
> Otherwise should continues to component_add()

We also should not continue if it is eDP in case of any error.

So it is if (is_edp || (!is_edp && ret != -ENODEV)) which is exactly
equivalent to (is_edp || ret != -ENODEV).

Could you please post the backtrace that you have observed?

> @@ -1210,7 +1210,9 @@ static int dp_display_probe_tail(struct device *dev)
>          dp->next_bridge = devm_drm_of_get_bridge(&dp->pdev->dev,
> dp->pdev->dev.of_node, 1, 0);
>          if (IS_ERR(dp->next_bridge)) {
>                  ret = PTR_ERR(dp->next_bridge);
> -               if (dp->is_edp || ret != -ENODEV)
> +               dp->next_bridge = NULL;
> +
> +               if (!dp->is_edp && ret != -ENODEV)
>                          return ret;
>          }
> >
> >>> On 12/29/2023 2:56 PM, Dmitry Baryshkov wrote:
> >>>> Remove two levels of indirection and fetch next bridge directly in
> >>>> dp_display_probe_tail().
> >>>>
> >>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> >>>> ---
> >>>>    drivers/gpu/drm/msm/dp/dp_display.c | 42
> >>>> +++++++++--------------------
> >>>>    drivers/gpu/drm/msm/dp/dp_parser.c  | 14 ----------
> >>>>    drivers/gpu/drm/msm/dp/dp_parser.h  | 14 ----------
> >>>>    3 files changed, 13 insertions(+), 57 deletions(-)

-- 
With best wishes
Dmitry