* Re: [PATCH] drm/msm/dp: make eDP panel as the first connected connector
@ 2022-06-30 1:57 ` Rob Clark
0 siblings, 0 replies; 16+ messages in thread
From: Rob Clark @ 2022-06-30 1:57 UTC (permalink / raw)
To: Doug Anderson
Cc: freedreno, Sankeerth Billakanti, David Airlie,
Kuogee Hsieh (QUIC), Abhinav Kumar (QUIC),
dri-devel, Stephen Boyd, Vinod Koul, Andy Gross, linux-arm-msm,
Dmitry Baryshkov, Aravind Venkateswaran (QUIC),
Bjorn Andersson, Sean Paul, LKML
On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
> >
> > On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
> > >Some userspace presumes that the first connected connector is the main
> > >display, where it's supposed to display e.g. the login screen. For
> > >laptops, this should be the main panel.
> > >
> > >This patch call drm_helper_move_panel_connectors_to_head() after
> > >drm_bridge_connector_init() to make sure eDP stay at head of
> > >connected connector list. This fixes unexpected corruption happen
> > >at eDP panel if eDP is not placed at head of connected connector
> > >list.
> >
> > The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
> > Also could you please describe the mind of corruption you are observing?
>
> I've spent a whole bunch of time poking at this and in the end my
> conclusion is this:
>
> 1. The glitchyness seems to be a result of the Chrome OS userspace
> somehow telling the kernel to do something wrong.
>
> 2. I believe (though I have no proof other than Kuogee's patch fixing
> things) that the Chrome OS userspace is simply confused by the eDP
> connector being second. This would imply that Kuogee's patch is
> actually the right one.
>
> 3. It would be ideal if the Chrome OS userspace were fixed to handle
> this, but it's an area of code that I've never looked at. It also
> seems terribly low priority to fix since apparently other OSes have
> similar problems (seems like this code was originally added by
> RedHat?)
>
>
> Specifically, I tested with a similar but "persistent" glitch that I
> reproduced. The glitch Kuogee was digging into was a transitory glitch
> on the eDP (internal) display when you plugged in a DP (external)
> display. It would show up for a frame or two and then be fixed. I can
> get a similar-looking glitch (vertical black and white bars) that
> persists by doing these steps on a Chrome OS device (and Chrome OS
> kernel):
>
> a) Observe screen looks good.
> b) Observe DP not connected.
> c) Plug in DP
> d) See transitory glitch on screen, then it all looks fine.
> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
> f) Wait for screen to turn off
> g) Unplug DP
> h) Hit key on keyboard to wake device.
> i) See glitchy.
> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
> --ac_screen_off_delay=10000
>
> Once I'm in the persistent glitch:
>
> * The "screenshot" command in Chrome OS shows corruption. Not exactly
> black and white bars, but the image produced has distinct bands of
> garbage.
>
> * I can actually toggle between VT2 and the main screen (VT1). Note
> that VT1/VT2 are not quite the normal Linux managed solution--I
> believe they're handled by frecon. In any case, when I switch to VT2
> it looks normal (I can see the login prompt). Then back to VT1 and the
> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
> glitch again. This implies (especially with the extra evidence of
> screenshot) that the display controller hardware is all fine and that
> it's the underlying data that's somehow messed up.
fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
simply just an un-renderered buffer being interpreted by the display
controller as UBWC (because userspace tells it to)
BR,
-R
> When I pick Kuogee's patch then this "persistent" glitch goes away
> just like the transitory one does.
>
> I'm going to go ahead and do:
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> Tested-by: Douglas Anderson <dianders@chromium.org>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Freedreno] [PATCH] drm/msm/dp: make eDP panel as the first connected connector
2022-06-30 1:57 ` Rob Clark
@ 2022-06-30 2:10 ` Abhinav Kumar
-1 siblings, 0 replies; 16+ messages in thread
From: Abhinav Kumar @ 2022-06-30 2:10 UTC (permalink / raw)
To: Rob Clark, Doug Anderson
Cc: freedreno, Sankeerth Billakanti, David Airlie,
Kuogee Hsieh (QUIC),
dri-devel, Stephen Boyd, Vinod Koul, Andy Gross, Daniel Vetter,
linux-arm-msm, Dmitry Baryshkov, Aravind Venkateswaran (QUIC),
Bjorn Andersson, Sean Paul, LKML
On 6/29/2022 6:57 PM, Rob Clark wrote:
> On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>>
>> Hi,
>>
>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>> <dmitry.baryshkov@linaro.org> wrote:
>>>
>>> On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>>>> Some userspace presumes that the first connected connector is the main
>>>> display, where it's supposed to display e.g. the login screen. For
>>>> laptops, this should be the main panel.
>>>>
>>>> This patch call drm_helper_move_panel_connectors_to_head() after
>>>> drm_bridge_connector_init() to make sure eDP stay at head of
>>>> connected connector list. This fixes unexpected corruption happen
>>>> at eDP panel if eDP is not placed at head of connected connector
>>>> list.
>>>
>>> The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
>>> Also could you please describe the mind of corruption you are observing?
>>
>> I've spent a whole bunch of time poking at this and in the end my
>> conclusion is this:
>>
>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>> somehow telling the kernel to do something wrong.
>>
>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>> things) that the Chrome OS userspace is simply confused by the eDP
>> connector being second. This would imply that Kuogee's patch is
>> actually the right one.
>>
>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>> this, but it's an area of code that I've never looked at. It also
>> seems terribly low priority to fix since apparently other OSes have
>> similar problems (seems like this code was originally added by
>> RedHat?)
>>
>>
>> Specifically, I tested with a similar but "persistent" glitch that I
>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>> on the eDP (internal) display when you plugged in a DP (external)
>> display. It would show up for a frame or two and then be fixed. I can
>> get a similar-looking glitch (vertical black and white bars) that
>> persists by doing these steps on a Chrome OS device (and Chrome OS
>> kernel):
>>
>> a) Observe screen looks good.
>> b) Observe DP not connected.
>> c) Plug in DP
>> d) See transitory glitch on screen, then it all looks fine.
>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>> f) Wait for screen to turn off
>> g) Unplug DP
>> h) Hit key on keyboard to wake device.
>> i) See glitchy.
>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>> --ac_screen_off_delay=10000
>>
>> Once I'm in the persistent glitch:
>>
>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>> black and white bars, but the image produced has distinct bands of
>> garbage.
>>
>> * I can actually toggle between VT2 and the main screen (VT1). Note
>> that VT1/VT2 are not quite the normal Linux managed solution--I
>> believe they're handled by frecon. In any case, when I switch to VT2
>> it looks normal (I can see the login prompt). Then back to VT1 and the
>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>> glitch again. This implies (especially with the extra evidence of
>> screenshot) that the display controller hardware is all fine and that
>> it's the underlying data that's somehow messed up.
>
> fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
> simply just an un-renderered buffer being interpreted by the display
> controller as UBWC (because userspace tells it to)
>
> BR,
> -R
Acked and agree with the comments both of you have stated and looking at
the corrupted buffers in the snapshot.
Hence,
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
>
>> When I pick Kuogee's patch then this "persistent" glitch goes away
>> just like the transitory one does.
>>
>> I'm going to go ahead and do:
>>
>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>> Tested-by: Douglas Anderson <dianders@chromium.org>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Freedreno] [PATCH] drm/msm/dp: make eDP panel as the first connected connector
@ 2022-06-30 2:10 ` Abhinav Kumar
0 siblings, 0 replies; 16+ messages in thread
From: Abhinav Kumar @ 2022-06-30 2:10 UTC (permalink / raw)
To: Rob Clark, Doug Anderson
Cc: Sean Paul, Sankeerth Billakanti, David Airlie, linux-arm-msm,
LKML, dri-devel, Stephen Boyd, Vinod Koul, Andy Gross,
Bjorn Andersson, Dmitry Baryshkov, Aravind Venkateswaran (QUIC),
Kuogee Hsieh (QUIC),
freedreno
On 6/29/2022 6:57 PM, Rob Clark wrote:
> On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>>
>> Hi,
>>
>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>> <dmitry.baryshkov@linaro.org> wrote:
>>>
>>> On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>>>> Some userspace presumes that the first connected connector is the main
>>>> display, where it's supposed to display e.g. the login screen. For
>>>> laptops, this should be the main panel.
>>>>
>>>> This patch call drm_helper_move_panel_connectors_to_head() after
>>>> drm_bridge_connector_init() to make sure eDP stay at head of
>>>> connected connector list. This fixes unexpected corruption happen
>>>> at eDP panel if eDP is not placed at head of connected connector
>>>> list.
>>>
>>> The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
>>> Also could you please describe the mind of corruption you are observing?
>>
>> I've spent a whole bunch of time poking at this and in the end my
>> conclusion is this:
>>
>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>> somehow telling the kernel to do something wrong.
>>
>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>> things) that the Chrome OS userspace is simply confused by the eDP
>> connector being second. This would imply that Kuogee's patch is
>> actually the right one.
>>
>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>> this, but it's an area of code that I've never looked at. It also
>> seems terribly low priority to fix since apparently other OSes have
>> similar problems (seems like this code was originally added by
>> RedHat?)
>>
>>
>> Specifically, I tested with a similar but "persistent" glitch that I
>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>> on the eDP (internal) display when you plugged in a DP (external)
>> display. It would show up for a frame or two and then be fixed. I can
>> get a similar-looking glitch (vertical black and white bars) that
>> persists by doing these steps on a Chrome OS device (and Chrome OS
>> kernel):
>>
>> a) Observe screen looks good.
>> b) Observe DP not connected.
>> c) Plug in DP
>> d) See transitory glitch on screen, then it all looks fine.
>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>> f) Wait for screen to turn off
>> g) Unplug DP
>> h) Hit key on keyboard to wake device.
>> i) See glitchy.
>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>> --ac_screen_off_delay=10000
>>
>> Once I'm in the persistent glitch:
>>
>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>> black and white bars, but the image produced has distinct bands of
>> garbage.
>>
>> * I can actually toggle between VT2 and the main screen (VT1). Note
>> that VT1/VT2 are not quite the normal Linux managed solution--I
>> believe they're handled by frecon. In any case, when I switch to VT2
>> it looks normal (I can see the login prompt). Then back to VT1 and the
>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>> glitch again. This implies (especially with the extra evidence of
>> screenshot) that the display controller hardware is all fine and that
>> it's the underlying data that's somehow messed up.
>
> fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
> simply just an un-renderered buffer being interpreted by the display
> controller as UBWC (because userspace tells it to)
>
> BR,
> -R
Acked and agree with the comments both of you have stated and looking at
the corrupted buffers in the snapshot.
Hence,
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
>
>> When I pick Kuogee's patch then this "persistent" glitch goes away
>> just like the transitory one does.
>>
>> I'm going to go ahead and do:
>>
>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>> Tested-by: Douglas Anderson <dianders@chromium.org>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] drm/msm/dp: make eDP panel as the first connected connector
2022-06-30 1:57 ` Rob Clark
@ 2022-06-30 6:14 ` Dmitry Baryshkov
-1 siblings, 0 replies; 16+ messages in thread
From: Dmitry Baryshkov @ 2022-06-30 6:14 UTC (permalink / raw)
To: Rob Clark, Doug Anderson
Cc: Sean Paul, Stephen Boyd, Vinod Koul, Daniel Vetter, David Airlie,
Andy Gross, Bjorn Andersson, Abhinav Kumar (QUIC),
Aravind Venkateswaran (QUIC), Kuogee Hsieh (QUIC),
Sankeerth Billakanti, freedreno, dri-devel, linux-arm-msm, LKML
On 30 June 2022 04:57:35 GMT+03:00, Rob Clark <robdclark@gmail.com> wrote:
>On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>>
>> Hi,
>>
>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>> <dmitry.baryshkov@linaro.org> wrote:
>> >
>> > On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>> > >Some userspace presumes that the first connected connector is the main
>> > >display, where it's supposed to display e.g. the login screen. For
>> > >laptops, this should be the main panel.
>> > >
>> > >This patch call drm_helper_move_panel_connectors_to_head() after
>> > >drm_bridge_connector_init() to make sure eDP stay at head of
>> > >connected connector list. This fixes unexpected corruption happen
>> > >at eDP panel if eDP is not placed at head of connected connector
>> > >list.
>> >
>> > The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
>> > Also could you please describe the mind of corruption you are observing?
>>
>> I've spent a whole bunch of time poking at this and in the end my
>> conclusion is this:
>>
>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>> somehow telling the kernel to do something wrong.
>>
>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>> things) that the Chrome OS userspace is simply confused by the eDP
>> connector being second. This would imply that Kuogee's patch is
>> actually the right one.
>>
>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>> this, but it's an area of code that I've never looked at. It also
>> seems terribly low priority to fix since apparently other OSes have
>> similar problems (seems like this code was originally added by
>> RedHat?)
>>
>>
>> Specifically, I tested with a similar but "persistent" glitch that I
>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>> on the eDP (internal) display when you plugged in a DP (external)
>> display. It would show up for a frame or two and then be fixed. I can
>> get a similar-looking glitch (vertical black and white bars) that
>> persists by doing these steps on a Chrome OS device (and Chrome OS
>> kernel):
>>
>> a) Observe screen looks good.
>> b) Observe DP not connected.
>> c) Plug in DP
>> d) See transitory glitch on screen, then it all looks fine.
>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>> f) Wait for screen to turn off
>> g) Unplug DP
>> h) Hit key on keyboard to wake device.
>> i) See glitchy.
>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>> --ac_screen_off_delay=10000
>>
>> Once I'm in the persistent glitch:
>>
>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>> black and white bars, but the image produced has distinct bands of
>> garbage.
>>
>> * I can actually toggle between VT2 and the main screen (VT1). Note
>> that VT1/VT2 are not quite the normal Linux managed solution--I
>> believe they're handled by frecon. In any case, when I switch to VT2
>> it looks normal (I can see the login prompt). Then back to VT1 and the
>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>> glitch again. This implies (especially with the extra evidence of
>> screenshot) that the display controller hardware is all fine and that
>> it's the underlying data that's somehow messed up.
>
>fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
>simply just an un-renderered buffer being interpreted by the display
>controller as UBWC (because userspace tells it to)
Thanks for the description. I think the userspace code should be fixed too, but this patch can go in on its own.
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>
>BR,
>-R
>
>> When I pick Kuogee's patch then this "persistent" glitch goes away
>> just like the transitory one does.
>>
>> I'm going to go ahead and do:
>>
>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>> Tested-by: Douglas Anderson <dianders@chromium.org>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] drm/msm/dp: make eDP panel as the first connected connector
@ 2022-06-30 6:14 ` Dmitry Baryshkov
0 siblings, 0 replies; 16+ messages in thread
From: Dmitry Baryshkov @ 2022-06-30 6:14 UTC (permalink / raw)
To: Rob Clark, Doug Anderson
Cc: freedreno, Sankeerth Billakanti, David Airlie,
Kuogee Hsieh (QUIC), Abhinav Kumar (QUIC),
dri-devel, Stephen Boyd, Vinod Koul, Andy Gross, linux-arm-msm,
Aravind Venkateswaran (QUIC),
Bjorn Andersson, Sean Paul, LKML
On 30 June 2022 04:57:35 GMT+03:00, Rob Clark <robdclark@gmail.com> wrote:
>On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>>
>> Hi,
>>
>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>> <dmitry.baryshkov@linaro.org> wrote:
>> >
>> > On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>> > >Some userspace presumes that the first connected connector is the main
>> > >display, where it's supposed to display e.g. the login screen. For
>> > >laptops, this should be the main panel.
>> > >
>> > >This patch call drm_helper_move_panel_connectors_to_head() after
>> > >drm_bridge_connector_init() to make sure eDP stay at head of
>> > >connected connector list. This fixes unexpected corruption happen
>> > >at eDP panel if eDP is not placed at head of connected connector
>> > >list.
>> >
>> > The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
>> > Also could you please describe the mind of corruption you are observing?
>>
>> I've spent a whole bunch of time poking at this and in the end my
>> conclusion is this:
>>
>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>> somehow telling the kernel to do something wrong.
>>
>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>> things) that the Chrome OS userspace is simply confused by the eDP
>> connector being second. This would imply that Kuogee's patch is
>> actually the right one.
>>
>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>> this, but it's an area of code that I've never looked at. It also
>> seems terribly low priority to fix since apparently other OSes have
>> similar problems (seems like this code was originally added by
>> RedHat?)
>>
>>
>> Specifically, I tested with a similar but "persistent" glitch that I
>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>> on the eDP (internal) display when you plugged in a DP (external)
>> display. It would show up for a frame or two and then be fixed. I can
>> get a similar-looking glitch (vertical black and white bars) that
>> persists by doing these steps on a Chrome OS device (and Chrome OS
>> kernel):
>>
>> a) Observe screen looks good.
>> b) Observe DP not connected.
>> c) Plug in DP
>> d) See transitory glitch on screen, then it all looks fine.
>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>> f) Wait for screen to turn off
>> g) Unplug DP
>> h) Hit key on keyboard to wake device.
>> i) See glitchy.
>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>> --ac_screen_off_delay=10000
>>
>> Once I'm in the persistent glitch:
>>
>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>> black and white bars, but the image produced has distinct bands of
>> garbage.
>>
>> * I can actually toggle between VT2 and the main screen (VT1). Note
>> that VT1/VT2 are not quite the normal Linux managed solution--I
>> believe they're handled by frecon. In any case, when I switch to VT2
>> it looks normal (I can see the login prompt). Then back to VT1 and the
>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>> glitch again. This implies (especially with the extra evidence of
>> screenshot) that the display controller hardware is all fine and that
>> it's the underlying data that's somehow messed up.
>
>fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
>simply just an un-renderered buffer being interpreted by the display
>controller as UBWC (because userspace tells it to)
Thanks for the description. I think the userspace code should be fixed too, but this patch can go in on its own.
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>
>BR,
>-R
>
>> When I pick Kuogee's patch then this "persistent" glitch goes away
>> just like the transitory one does.
>>
>> I'm going to go ahead and do:
>>
>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>> Tested-by: Douglas Anderson <dianders@chromium.org>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] drm/msm/dp: make eDP panel as the first connected connector
2022-06-30 6:14 ` Dmitry Baryshkov
@ 2022-07-04 18:14 ` Dmitry Baryshkov
-1 siblings, 0 replies; 16+ messages in thread
From: Dmitry Baryshkov @ 2022-07-04 18:14 UTC (permalink / raw)
To: Rob Clark, Doug Anderson, Kuogee Hsieh
Cc: Sean Paul, Stephen Boyd, Vinod Koul, Daniel Vetter, David Airlie,
Andy Gross, Bjorn Andersson, Abhinav Kumar (QUIC),
Aravind Venkateswaran (QUIC), Kuogee Hsieh (QUIC),
Sankeerth Billakanti, freedreno, dri-devel, linux-arm-msm, LKML
On 30/06/2022 09:14, Dmitry Baryshkov wrote:
>
>
> On 30 June 2022 04:57:35 GMT+03:00, Rob Clark <robdclark@gmail.com> wrote:
>> On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>>>
>>> Hi,
>>>
>>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>>> <dmitry.baryshkov@linaro.org> wrote:
>>>>
>>>> On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>>>>> Some userspace presumes that the first connected connector is the main
>>>>> display, where it's supposed to display e.g. the login screen. For
>>>>> laptops, this should be the main panel.
>>>>>
>>>>> This patch call drm_helper_move_panel_connectors_to_head() after
>>>>> drm_bridge_connector_init() to make sure eDP stay at head of
>>>>> connected connector list. This fixes unexpected corruption happen
>>>>> at eDP panel if eDP is not placed at head of connected connector
>>>>> list.
>>>>
>>>> The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
>>>> Also could you please describe the mind of corruption you are observing?
>>>
>>> I've spent a whole bunch of time poking at this and in the end my
>>> conclusion is this:
>>>
>>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>>> somehow telling the kernel to do something wrong.
>>>
>>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>>> things) that the Chrome OS userspace is simply confused by the eDP
>>> connector being second. This would imply that Kuogee's patch is
>>> actually the right one.
>>>
>>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>>> this, but it's an area of code that I've never looked at. It also
>>> seems terribly low priority to fix since apparently other OSes have
>>> similar problems (seems like this code was originally added by
>>> RedHat?)
>>>
>>>
>>> Specifically, I tested with a similar but "persistent" glitch that I
>>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>>> on the eDP (internal) display when you plugged in a DP (external)
>>> display. It would show up for a frame or two and then be fixed. I can
>>> get a similar-looking glitch (vertical black and white bars) that
>>> persists by doing these steps on a Chrome OS device (and Chrome OS
>>> kernel):
>>>
>>> a) Observe screen looks good.
>>> b) Observe DP not connected.
>>> c) Plug in DP
>>> d) See transitory glitch on screen, then it all looks fine.
>>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>>> f) Wait for screen to turn off
>>> g) Unplug DP
>>> h) Hit key on keyboard to wake device.
>>> i) See glitchy.
>>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>>> --ac_screen_off_delay=10000
>>>
>>> Once I'm in the persistent glitch:
>>>
>>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>>> black and white bars, but the image produced has distinct bands of
>>> garbage.
>>>
>>> * I can actually toggle between VT2 and the main screen (VT1). Note
>>> that VT1/VT2 are not quite the normal Linux managed solution--I
>>> believe they're handled by frecon. In any case, when I switch to VT2
>>> it looks normal (I can see the login prompt). Then back to VT1 and the
>>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>>> glitch again. This implies (especially with the extra evidence of
>>> screenshot) that the display controller hardware is all fine and that
>>> it's the underlying data that's somehow messed up.
>>
>> fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
>> simply just an un-renderered buffer being interpreted by the display
>> controller as UBWC (because userspace tells it to)
>
> Thanks for the description. I think the userspace code should be fixed too, but this patch can go in on its own.
>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
After some time (please excuse me), musing with the code and even
picking up the commit for the merge branch, I understood the fact that I
did not like about this change. It moves all panel connectors (generic
code) from the DP-specific driver.
I'd like to retract my R-b. Please move this call to the msm_drm_init().
Calling this function somewhere after the ->kms_init() would make sure
that all panel connectors are close to the top of the list, whichever
MDP/DPU driver is used and whichever actual interface is bound to this
panel.
>
>
>>
>> BR,
>> -R
>>
>>> When I pick Kuogee's patch then this "persistent" glitch goes away
>>> just like the transitory one does.
>>>
>>> I'm going to go ahead and do:
>>>
>>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>>> Tested-by: Douglas Anderson <dianders@chromium.org>
>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] drm/msm/dp: make eDP panel as the first connected connector
@ 2022-07-04 18:14 ` Dmitry Baryshkov
0 siblings, 0 replies; 16+ messages in thread
From: Dmitry Baryshkov @ 2022-07-04 18:14 UTC (permalink / raw)
To: Rob Clark, Doug Anderson, Kuogee Hsieh
Cc: freedreno, Sankeerth Billakanti, David Airlie,
Kuogee Hsieh (QUIC), Abhinav Kumar (QUIC),
dri-devel, Stephen Boyd, Vinod Koul, Andy Gross, linux-arm-msm,
Aravind Venkateswaran (QUIC),
Bjorn Andersson, Sean Paul, LKML
On 30/06/2022 09:14, Dmitry Baryshkov wrote:
>
>
> On 30 June 2022 04:57:35 GMT+03:00, Rob Clark <robdclark@gmail.com> wrote:
>> On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org> wrote:
>>>
>>> Hi,
>>>
>>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>>> <dmitry.baryshkov@linaro.org> wrote:
>>>>
>>>> On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh <quic_khsieh@quicinc.com> wrote:
>>>>> Some userspace presumes that the first connected connector is the main
>>>>> display, where it's supposed to display e.g. the login screen. For
>>>>> laptops, this should be the main panel.
>>>>>
>>>>> This patch call drm_helper_move_panel_connectors_to_head() after
>>>>> drm_bridge_connector_init() to make sure eDP stay at head of
>>>>> connected connector list. This fixes unexpected corruption happen
>>>>> at eDP panel if eDP is not placed at head of connected connector
>>>>> list.
>>>>
>>>> The change itself is a good fix anyway. (And I'd ack it.) However I would like to understand why does it fix the corruption issue. What is we have eDP and DSI, with DSI ending up before the eDP? Would we see the issue?
>>>> Also could you please describe the mind of corruption you are observing?
>>>
>>> I've spent a whole bunch of time poking at this and in the end my
>>> conclusion is this:
>>>
>>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>>> somehow telling the kernel to do something wrong.
>>>
>>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>>> things) that the Chrome OS userspace is simply confused by the eDP
>>> connector being second. This would imply that Kuogee's patch is
>>> actually the right one.
>>>
>>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>>> this, but it's an area of code that I've never looked at. It also
>>> seems terribly low priority to fix since apparently other OSes have
>>> similar problems (seems like this code was originally added by
>>> RedHat?)
>>>
>>>
>>> Specifically, I tested with a similar but "persistent" glitch that I
>>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>>> on the eDP (internal) display when you plugged in a DP (external)
>>> display. It would show up for a frame or two and then be fixed. I can
>>> get a similar-looking glitch (vertical black and white bars) that
>>> persists by doing these steps on a Chrome OS device (and Chrome OS
>>> kernel):
>>>
>>> a) Observe screen looks good.
>>> b) Observe DP not connected.
>>> c) Plug in DP
>>> d) See transitory glitch on screen, then it all looks fine.
>>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>>> f) Wait for screen to turn off
>>> g) Unplug DP
>>> h) Hit key on keyboard to wake device.
>>> i) See glitchy.
>>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>>> --ac_screen_off_delay=10000
>>>
>>> Once I'm in the persistent glitch:
>>>
>>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>>> black and white bars, but the image produced has distinct bands of
>>> garbage.
>>>
>>> * I can actually toggle between VT2 and the main screen (VT1). Note
>>> that VT1/VT2 are not quite the normal Linux managed solution--I
>>> believe they're handled by frecon. In any case, when I switch to VT2
>>> it looks normal (I can see the login prompt). Then back to VT1 and the
>>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>>> glitch again. This implies (especially with the extra evidence of
>>> screenshot) that the display controller hardware is all fine and that
>>> it's the underlying data that's somehow messed up.
>>
>> fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
>> simply just an un-renderered buffer being interpreted by the display
>> controller as UBWC (because userspace tells it to)
>
> Thanks for the description. I think the userspace code should be fixed too, but this patch can go in on its own.
>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
After some time (please excuse me), musing with the code and even
picking up the commit for the merge branch, I understood the fact that I
did not like about this change. It moves all panel connectors (generic
code) from the DP-specific driver.
I'd like to retract my R-b. Please move this call to the msm_drm_init().
Calling this function somewhere after the ->kms_init() would make sure
that all panel connectors are close to the top of the list, whichever
MDP/DPU driver is used and whichever actual interface is bound to this
panel.
>
>
>>
>> BR,
>> -R
>>
>>> When I pick Kuogee's patch then this "persistent" glitch goes away
>>> just like the transitory one does.
>>>
>>> I'm going to go ahead and do:
>>>
>>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>>> Tested-by: Douglas Anderson <dianders@chromium.org>
>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Freedreno] [PATCH] drm/msm/dp: make eDP panel as the first connected connector
2022-07-04 18:14 ` Dmitry Baryshkov
@ 2022-07-05 5:41 ` Abhinav Kumar
-1 siblings, 0 replies; 16+ messages in thread
From: Abhinav Kumar @ 2022-07-05 5:41 UTC (permalink / raw)
To: Dmitry Baryshkov, Rob Clark, Doug Anderson, Kuogee Hsieh
Cc: freedreno, Sankeerth Billakanti, David Airlie, dri-devel,
Stephen Boyd, Vinod Koul, Andy Gross, Daniel Vetter,
linux-arm-msm, Aravind Venkateswaran (QUIC),
Bjorn Andersson, Sean Paul, LKML
On 7/4/2022 11:14 AM, Dmitry Baryshkov wrote:
> On 30/06/2022 09:14, Dmitry Baryshkov wrote:
>>
>>
>> On 30 June 2022 04:57:35 GMT+03:00, Rob Clark <robdclark@gmail.com>
>> wrote:
>>> On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>>>> <dmitry.baryshkov@linaro.org> wrote:
>>>>>
>>>>> On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh
>>>>> <quic_khsieh@quicinc.com> wrote:
>>>>>> Some userspace presumes that the first connected connector is the
>>>>>> main
>>>>>> display, where it's supposed to display e.g. the login screen. For
>>>>>> laptops, this should be the main panel.
>>>>>>
>>>>>> This patch call drm_helper_move_panel_connectors_to_head() after
>>>>>> drm_bridge_connector_init() to make sure eDP stay at head of
>>>>>> connected connector list. This fixes unexpected corruption happen
>>>>>> at eDP panel if eDP is not placed at head of connected connector
>>>>>> list.
>>>>>
>>>>> The change itself is a good fix anyway. (And I'd ack it.) However I
>>>>> would like to understand why does it fix the corruption issue. What
>>>>> is we have eDP and DSI, with DSI ending up before the eDP? Would we
>>>>> see the issue?
>>>>> Also could you please describe the mind of corruption you are
>>>>> observing?
>>>>
>>>> I've spent a whole bunch of time poking at this and in the end my
>>>> conclusion is this:
>>>>
>>>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>>>> somehow telling the kernel to do something wrong.
>>>>
>>>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>>>> things) that the Chrome OS userspace is simply confused by the eDP
>>>> connector being second. This would imply that Kuogee's patch is
>>>> actually the right one.
>>>>
>>>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>>>> this, but it's an area of code that I've never looked at. It also
>>>> seems terribly low priority to fix since apparently other OSes have
>>>> similar problems (seems like this code was originally added by
>>>> RedHat?)
>>>>
>>>>
>>>> Specifically, I tested with a similar but "persistent" glitch that I
>>>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>>>> on the eDP (internal) display when you plugged in a DP (external)
>>>> display. It would show up for a frame or two and then be fixed. I can
>>>> get a similar-looking glitch (vertical black and white bars) that
>>>> persists by doing these steps on a Chrome OS device (and Chrome OS
>>>> kernel):
>>>>
>>>> a) Observe screen looks good.
>>>> b) Observe DP not connected.
>>>> c) Plug in DP
>>>> d) See transitory glitch on screen, then it all looks fine.
>>>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>>>> f) Wait for screen to turn off
>>>> g) Unplug DP
>>>> h) Hit key on keyboard to wake device.
>>>> i) See glitchy.
>>>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>>>> --ac_screen_off_delay=10000
>>>>
>>>> Once I'm in the persistent glitch:
>>>>
>>>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>>>> black and white bars, but the image produced has distinct bands of
>>>> garbage.
>>>>
>>>> * I can actually toggle between VT2 and the main screen (VT1). Note
>>>> that VT1/VT2 are not quite the normal Linux managed solution--I
>>>> believe they're handled by frecon. In any case, when I switch to VT2
>>>> it looks normal (I can see the login prompt). Then back to VT1 and the
>>>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>>>> glitch again. This implies (especially with the extra evidence of
>>>> screenshot) that the display controller hardware is all fine and that
>>>> it's the underlying data that's somehow messed up.
>>>
>>> fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
>>> simply just an un-renderered buffer being interpreted by the display
>>> controller as UBWC (because userspace tells it to)
>>
>> Thanks for the description. I think the userspace code should be fixed
>> too, but this patch can go in on its own.
>>
>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>
> After some time (please excuse me), musing with the code and even
> picking up the commit for the merge branch, I understood the fact that I
> did not like about this change. It moves all panel connectors (generic
> code) from the DP-specific driver.
>
> I'd like to retract my R-b. Please move this call to the msm_drm_init().
> Calling this function somewhere after the ->kms_init() would make sure
> that all panel connectors are close to the top of the list, whichever
> MDP/DPU driver is used and whichever actual interface is bound to this
> panel.
>
Ah. True, but just to add. It should be after kms_init() but before
drm_dev_register().
>>
>>
>>>
>>> BR,
>>> -R
>>>
>>>> When I pick Kuogee's patch then this "persistent" glitch goes away
>>>> just like the transitory one does.
>>>>
>>>> I'm going to go ahead and do:
>>>>
>>>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>>>> Tested-by: Douglas Anderson <dianders@chromium.org>
>>
>
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Freedreno] [PATCH] drm/msm/dp: make eDP panel as the first connected connector
@ 2022-07-05 5:41 ` Abhinav Kumar
0 siblings, 0 replies; 16+ messages in thread
From: Abhinav Kumar @ 2022-07-05 5:41 UTC (permalink / raw)
To: Dmitry Baryshkov, Rob Clark, Doug Anderson, Kuogee Hsieh
Cc: Sean Paul, Sankeerth Billakanti, David Airlie, linux-arm-msm,
LKML, dri-devel, Stephen Boyd, Vinod Koul, Andy Gross,
Aravind Venkateswaran (QUIC),
Bjorn Andersson, freedreno
On 7/4/2022 11:14 AM, Dmitry Baryshkov wrote:
> On 30/06/2022 09:14, Dmitry Baryshkov wrote:
>>
>>
>> On 30 June 2022 04:57:35 GMT+03:00, Rob Clark <robdclark@gmail.com>
>> wrote:
>>> On Wed, Jun 29, 2022 at 5:36 PM Doug Anderson <dianders@chromium.org>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On Tue, Jun 28, 2022 at 1:14 PM Dmitry Baryshkov
>>>> <dmitry.baryshkov@linaro.org> wrote:
>>>>>
>>>>> On 28 June 2022 18:20:06 GMT+03:00, Kuogee Hsieh
>>>>> <quic_khsieh@quicinc.com> wrote:
>>>>>> Some userspace presumes that the first connected connector is the
>>>>>> main
>>>>>> display, where it's supposed to display e.g. the login screen. For
>>>>>> laptops, this should be the main panel.
>>>>>>
>>>>>> This patch call drm_helper_move_panel_connectors_to_head() after
>>>>>> drm_bridge_connector_init() to make sure eDP stay at head of
>>>>>> connected connector list. This fixes unexpected corruption happen
>>>>>> at eDP panel if eDP is not placed at head of connected connector
>>>>>> list.
>>>>>
>>>>> The change itself is a good fix anyway. (And I'd ack it.) However I
>>>>> would like to understand why does it fix the corruption issue. What
>>>>> is we have eDP and DSI, with DSI ending up before the eDP? Would we
>>>>> see the issue?
>>>>> Also could you please describe the mind of corruption you are
>>>>> observing?
>>>>
>>>> I've spent a whole bunch of time poking at this and in the end my
>>>> conclusion is this:
>>>>
>>>> 1. The glitchyness seems to be a result of the Chrome OS userspace
>>>> somehow telling the kernel to do something wrong.
>>>>
>>>> 2. I believe (though I have no proof other than Kuogee's patch fixing
>>>> things) that the Chrome OS userspace is simply confused by the eDP
>>>> connector being second. This would imply that Kuogee's patch is
>>>> actually the right one.
>>>>
>>>> 3. It would be ideal if the Chrome OS userspace were fixed to handle
>>>> this, but it's an area of code that I've never looked at. It also
>>>> seems terribly low priority to fix since apparently other OSes have
>>>> similar problems (seems like this code was originally added by
>>>> RedHat?)
>>>>
>>>>
>>>> Specifically, I tested with a similar but "persistent" glitch that I
>>>> reproduced. The glitch Kuogee was digging into was a transitory glitch
>>>> on the eDP (internal) display when you plugged in a DP (external)
>>>> display. It would show up for a frame or two and then be fixed. I can
>>>> get a similar-looking glitch (vertical black and white bars) that
>>>> persists by doing these steps on a Chrome OS device (and Chrome OS
>>>> kernel):
>>>>
>>>> a) Observe screen looks good.
>>>> b) Observe DP not connected.
>>>> c) Plug in DP
>>>> d) See transitory glitch on screen, then it all looks fine.
>>>> e) set_power_policy --ac_screen_dim_delay=5 --ac_screen_off_delay=10
>>>> f) Wait for screen to turn off
>>>> g) Unplug DP
>>>> h) Hit key on keyboard to wake device.
>>>> i) See glitchy.
>>>> j) Within 5 seconds: set_power_policy --ac_screen_dim_delay=5000
>>>> --ac_screen_off_delay=10000
>>>>
>>>> Once I'm in the persistent glitch:
>>>>
>>>> * The "screenshot" command in Chrome OS shows corruption. Not exactly
>>>> black and white bars, but the image produced has distinct bands of
>>>> garbage.
>>>>
>>>> * I can actually toggle between VT2 and the main screen (VT1). Note
>>>> that VT1/VT2 are not quite the normal Linux managed solution--I
>>>> believe they're handled by frecon. In any case, when I switch to VT2
>>>> it looks normal (I can see the login prompt). Then back to VT1 and the
>>>> vertical bars glitch. Back to VT2 and it's normal. Back to VT1 and the
>>>> glitch again. This implies (especially with the extra evidence of
>>>> screenshot) that the display controller hardware is all fine and that
>>>> it's the underlying data that's somehow messed up.
>>>
>>> fwiw, from looking at this a bit w/ Doug, I think the "glitch" is
>>> simply just an un-renderered buffer being interpreted by the display
>>> controller as UBWC (because userspace tells it to)
>>
>> Thanks for the description. I think the userspace code should be fixed
>> too, but this patch can go in on its own.
>>
>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>
> After some time (please excuse me), musing with the code and even
> picking up the commit for the merge branch, I understood the fact that I
> did not like about this change. It moves all panel connectors (generic
> code) from the DP-specific driver.
>
> I'd like to retract my R-b. Please move this call to the msm_drm_init().
> Calling this function somewhere after the ->kms_init() would make sure
> that all panel connectors are close to the top of the list, whichever
> MDP/DPU driver is used and whichever actual interface is bound to this
> panel.
>
Ah. True, but just to add. It should be after kms_init() but before
drm_dev_register().
>>
>>
>>>
>>> BR,
>>> -R
>>>
>>>> When I pick Kuogee's patch then this "persistent" glitch goes away
>>>> just like the transitory one does.
>>>>
>>>> I'm going to go ahead and do:
>>>>
>>>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>>>> Tested-by: Douglas Anderson <dianders@chromium.org>
>>
>
>
^ permalink raw reply [flat|nested] 16+ messages in thread