Messages in this thread | | | Date | Wed, 14 Apr 2021 10:55:09 -0700 | From | khsieh@codeauro ... | Subject | Re: [PATCH v2 2/3] drm/msm/dp: do not re initialize of audio_comp at display_disable() |
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On 2021-04-13 20:17, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2021-04-13 16:11:30) >> At dongle unplug, dp initializes audio_comp followed by sending >> disconnect >> event notification to audio and to make sure audio had shutdown >> completely >> by wait for audio completion notification at display_disable(). This >> patch > > Is this dp_display_disable()? Doubtful that display_disable() is the > function we're talking about. yes > >> will not re initialize audio_comp at display_disable() if audio >> shutdown >> is triggered by dongle unplugged. > > This commit text seems to say the why before the what, where why is "dp > initializes audio_comp followed by sending disconnect.." and the what > is > "this patch will no re-initialized audio_comp...". Can you reorder this > so the what comes before the why? > ok >> >> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org> >> --- >> drivers/gpu/drm/msm/dp/dp_display.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c >> b/drivers/gpu/drm/msm/dp/dp_display.c >> index 0ba71c7..1d71c95 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_display.c >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c >> @@ -894,8 +894,10 @@ static int dp_display_disable(struct >> dp_display_private *dp, u32 data) >> /* wait only if audio was enabled */ >> if (dp_display->audio_enabled) { >> /* signal the disconnect event */ >> - reinit_completion(&dp->audio_comp); >> - dp_display_handle_plugged_change(dp_display, false); >> + if (dp->hpd_state != ST_DISCONNECT_PENDING) { >> + reinit_completion(&dp->audio_comp); > > Why is this reinitialized here at all? Wouldn't it make more sense to > initialize the completion once at cable plug in and then not initialize > the completion anywhere else? Or initialize the completion whenever > dp_display->audio_enabled is set to true and then only wait for the > completion here if that boolean is true? Or initialize the completion > when dp_display_handle_plugged_change() is passed true for the > 'plugged' > argument? > yes, i think it is better approach, this will take care of both unplug > and suspend.
> I started reading the code and quickly got lost figuring out how > dp_display_handle_plugged_change() worked and the interaction between > the dp display code and the audio codec embedded in here. There seem to > be a couple of conditions that cut off things early, like > dp_display->audio_enabled and audio->engine_on. Why? Why does > dp_display_signal_audio_complete() call complete_all() vs. just > complete()? Please help! :( > >> + dp_display_handle_plugged_change(dp_display, >> false); > > I think it's this way because dp_hpd_unplug_handle() is the function > that sets the hpd_state to ST_DISCONNECT_PENDING and then reinitializes > the completion (why?) and calls dp_display_handle_plugged_change(). So > the commit text could say that reinitializing the completion again here > at dp_display_disable() is racing with the audio code in the case that > dp_hpd_unplug_handle() already called > dp_display_handle_plugged_change() and it would make more sense. But > the > question still stands why that race even exists in the first place vs. > initializing the completion variable in only one place unconditionally > when the cable is connected, in dp_hpd_plug_handle() or > dp_display_post_enable(). > >> + } >> if (!wait_for_completion_timeout(&dp->audio_comp, >> HZ * 5)) >> DRM_ERROR("audio comp timeout\n");
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