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Groups > linux.kernel > #1666261 > unrolled thread

[BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

Started byAaro Koskinen <aaro.koskinen@iki.fi>
First post2017-06-15 00:20 +0200
Last post2017-06-18 23:50 +0200
Articles 5 — 3 participants

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  [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900 Aaro Koskinen <aaro.koskinen@iki.fi> - 2017-06-15 00:20 +0200
    Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia  N900 Tomi Valkeinen <tomi.valkeinen@ti.com> - 2017-06-15 09:00 +0200
      Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia  N900 Aaro Koskinen <aaro.koskinen@iki.fi> - 2017-06-18 23:40 +0200
    Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia  N900 Peter Ujfalusi <peter.ujfalusi@ti.com> - 2017-06-15 09:30 +0200
      Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia  N900 Aaro Koskinen <aaro.koskinen@iki.fi> - 2017-06-18 23:50 +0200

#1666261 — [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

FromAaro Koskinen <aaro.koskinen@iki.fi>
Date2017-06-15 00:20 +0200
Subject[BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900
Message-ID<tSoNP-2uY-3@gated-at.bofh.it>
Hi,

When booting v4.12-rc5 on Nokia N900, omapdrm fails to probe and there
is no display.

Bisected to:

a09d2bc1503508c17ef3a71c6b1905e3660f3029 is the first bad commit
commit a09d2bc1503508c17ef3a71c6b1905e3660f3029
Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
Date:   Tue May 3 22:08:01 2016 +0300

    drm/omap: Use omapdss_stack_is_ready() to check that the display stack is up
    
    Instead of 'guessing' based on aliases of the status of the DSS drivers,
    use the new interface to check that all needed drivers are loaded.
    In this way we can be sure that all needed drivers are loaded so it is
    safe to continue the probing of omapdrm.
    This method will allow the omapdrm to be probed 'headless', without
    outputs.
    
    Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
    Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Reverting the commit seems to fix the issue.

A.

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#1666497 — Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

FromTomi Valkeinen <tomi.valkeinen@ti.com>
Date2017-06-15 09:00 +0200
SubjectRe: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900
Message-ID<tSwV4-7xc-21@gated-at.bofh.it>
In reply to#1666261

[Multipart message — attachments visible in raw view] — view raw

On 15/06/17 01:11, Aaro Koskinen wrote:
> Hi,
> 
> When booting v4.12-rc5 on Nokia N900, omapdrm fails to probe and there
> is no display.

Are you sure it doesn't probe? It fails the omapdss_stack_is_ready()
check? If that's the case then this is easier to debug.

> Bisected to:
> 
> a09d2bc1503508c17ef3a71c6b1905e3660f3029 is the first bad commit
> commit a09d2bc1503508c17ef3a71c6b1905e3660f3029
> Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
> Date:   Tue May 3 22:08:01 2016 +0300
> 
>     drm/omap: Use omapdss_stack_is_ready() to check that the display stack is up
>     
>     Instead of 'guessing' based on aliases of the status of the DSS drivers,
>     use the new interface to check that all needed drivers are loaded.
>     In this way we can be sure that all needed drivers are loaded so it is
>     safe to continue the probing of omapdrm.
>     This method will allow the omapdrm to be probed 'headless', without
>     outputs.
>     
>     Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>     Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> 
> Reverting the commit seems to fix the issue.

This is probably "fixed" by adding the display aliases into the n900 dts
file. The aliases should not really be required, although they are
recommended. Without the aliases the order of the displays is random,
and n900 could end up using tv-out as the first display. But even then,
the displays should still work.

 Tomi

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#1668660 — Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

FromAaro Koskinen <aaro.koskinen@iki.fi>
Date2017-06-18 23:40 +0200
SubjectRe: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900
Message-ID<tTQ5k-22c-27@gated-at.bofh.it>
In reply to#1666497
Hi,

On Thu, Jun 15, 2017 at 09:51:06AM +0300, Tomi Valkeinen wrote:
> On 15/06/17 01:11, Aaro Koskinen wrote:
> > When booting v4.12-rc5 on Nokia N900, omapdrm fails to probe and there
> > is no display.
> 
> Are you sure it doesn't probe? It fails the omapdss_stack_is_ready()
> check? If that's the case then this is easier to debug.

Yes I think so, I added debug prints to omap_connect_dssdevs() and
pdev_probe(), and it's omapdss_stack_is_ready() that is failing.

> > Bisected to:
> > 
> > a09d2bc1503508c17ef3a71c6b1905e3660f3029 is the first bad commit
> > commit a09d2bc1503508c17ef3a71c6b1905e3660f3029
> > Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
> > Date:   Tue May 3 22:08:01 2016 +0300
> > 
> >     drm/omap: Use omapdss_stack_is_ready() to check that the display stack is up
> >     
> >     Instead of 'guessing' based on aliases of the status of the DSS drivers,
> >     use the new interface to check that all needed drivers are loaded.
> >     In this way we can be sure that all needed drivers are loaded so it is
> >     safe to continue the probing of omapdrm.
> >     This method will allow the omapdrm to be probed 'headless', without
> >     outputs.
> >     
> >     Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> >     Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > 
> > Reverting the commit seems to fix the issue.
> 
> This is probably "fixed" by adding the display aliases into the n900 dts
> file. The aliases should not really be required, although they are
> recommended. Without the aliases the order of the displays is random,
> and n900 could end up using tv-out as the first display. But even then,
> the displays should still work.

I'm using up-to-date DTS from the kernel tree.

A.

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#1666513 — Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

FromPeter Ujfalusi <peter.ujfalusi@ti.com>
Date2017-06-15 09:30 +0200
SubjectRe: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900
Message-ID<tSxo5-7X3-3@gated-at.bofh.it>
In reply to#1666261

On 2017-06-15 01:11, Aaro Koskinen wrote:
> Hi,
> 
> When booting v4.12-rc5 on Nokia N900, omapdrm fails to probe and there
> is no display.
> 
> Bisected to:
> 
> a09d2bc1503508c17ef3a71c6b1905e3660f3029 is the first bad commit
> commit a09d2bc1503508c17ef3a71c6b1905e3660f3029
> Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
> Date:   Tue May 3 22:08:01 2016 +0300
> 
>     drm/omap: Use omapdss_stack_is_ready() to check that the display stack is up
>     
>     Instead of 'guessing' based on aliases of the status of the DSS drivers,
>     use the new interface to check that all needed drivers are loaded.
>     In this way we can be sure that all needed drivers are loaded so it is
>     safe to continue the probing of omapdrm.
>     This method will allow the omapdrm to be probed 'headless', without
>     outputs.
>     
>     Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>     Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> 
> Reverting the commit seems to fix the issue.

When you revert this patch do you see a warning saying:
"could not connect display: blah" ? if so what is 'blah'?

n900 have two displays afaik, LCD and TVout. omapdss_stack_is_ready() is
to ensure that we have all the drivers loaded for both displays, while
by reverting it it is enough if one of them is loaded at the time we do
the check and omapdrm would continue to probe, but the missing display
(even if it is going to be probed a bit later) will not work.

- Péter

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#1668662 — Re: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900

FromAaro Koskinen <aaro.koskinen@iki.fi>
Date2017-06-18 23:50 +0200
SubjectRe: [BISECTED, REGRESSION] v4.12-rc: omapdrm fails to probe on Nokia N900
Message-ID<tTQeZ-269-1@gated-at.bofh.it>
In reply to#1666513
Hi,

On Thu, Jun 15, 2017 at 10:28:31AM +0300, Peter Ujfalusi wrote:
> On 2017-06-15 01:11, Aaro Koskinen wrote:
> > When booting v4.12-rc5 on Nokia N900, omapdrm fails to probe and there
> > is no display.
> > 
> > Bisected to:
> > 
> > a09d2bc1503508c17ef3a71c6b1905e3660f3029 is the first bad commit
> > commit a09d2bc1503508c17ef3a71c6b1905e3660f3029
> > Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
> > Date:   Tue May 3 22:08:01 2016 +0300
> > 
> >     drm/omap: Use omapdss_stack_is_ready() to check that the display stack is up
> >     
> >     Instead of 'guessing' based on aliases of the status of the DSS drivers,
> >     use the new interface to check that all needed drivers are loaded.
> >     In this way we can be sure that all needed drivers are loaded so it is
> >     safe to continue the probing of omapdrm.
> >     This method will allow the omapdrm to be probed 'headless', without
> >     outputs.
> >     
> >     Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> >     Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > 
> > Reverting the commit seems to fix the issue.
> 
> When you revert this patch do you see a warning saying:
> "could not connect display: blah" ? if so what is 'blah'?

No.

A.

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