[PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Thomas Zimmermann]

As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
the option to fix the build failure. The error message is shown
below.

  arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
    `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
    `drm_panel_dp_aux_backlight'
  make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1

The issue has been reported before, when DisplayPort helpers were
hidden behind the option CONFIG_DRM_KMS_HELPER. [2]

v2:
	* fix and expand commit description (Arnd)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: adb9d5a2cc77 ("drm/dp: Move DisplayPort helpers into separate helper module")
Fixes: 5f04e7ce392d ("drm/panel-edp: Split eDP panels out of panel-simple")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Link: https://lore.kernel.org/dri-devel/CA+G9fYvN0NyaVkRQmA1O6rX7H8PPaZrUAD7=RDy33QY9rUU-9g@mail.gmail.com/ # [1]
Link: https://lore.kernel.org/all/20211117062704.14671-1-rdunlap@infradead.org/ # [2]
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/panel/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 434c2861bb40..0aec5a10b064 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -106,6 +106,7 @@ config DRM_PANEL_EDP
 	depends on PM
 	select VIDEOMODE_HELPERS
 	select DRM_DP_AUX_BUS
+	select DRM_DP_HELPER
 	help
 	  DRM panel driver for dumb eDP panels that need at most a regulator and
 	  a GPIO to be powered up. Optionally a backlight can be attached so
-- 
2.34.1

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Sam Ravnborg]

On Thu, Feb 03, 2022 at 10:39:22AM +0100, Thomas Zimmermann wrote:
> As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
> the option to fix the build failure. The error message is shown
> below.
> 
>   arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
>     `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
>     `drm_panel_dp_aux_backlight'
>   make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
> 
> The issue has been reported before, when DisplayPort helpers were
> hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
> 
> v2:
> 	* fix and expand commit description (Arnd)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Fixes: adb9d5a2cc77 ("drm/dp: Move DisplayPort helpers into separate helper module")
> Fixes: 5f04e7ce392d ("drm/panel-edp: Split eDP panels out of panel-simple")
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Link: https://lore.kernel.org/dri-devel/CA+G9fYvN0NyaVkRQmA1O6rX7H8PPaZrUAD7=RDy33QY9rUU-9g@mail.gmail.com/ # [1]
> Link: https://lore.kernel.org/all/20211117062704.14671-1-rdunlap@infradead.org/ # [2]
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: dri-devel@lists.freedesktop.org

Acked-by: Sam Ravnborg <sam@ravnborg.org>

> ---
>  drivers/gpu/drm/panel/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 434c2861bb40..0aec5a10b064 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -106,6 +106,7 @@ config DRM_PANEL_EDP
>  	depends on PM
>  	select VIDEOMODE_HELPERS
>  	select DRM_DP_AUX_BUS
> +	select DRM_DP_HELPER
>  	help
>  	  DRM panel driver for dumb eDP panels that need at most a regulator and
>  	  a GPIO to be powered up. Optionally a backlight can be attached so
> -- 
> 2.34.1

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Naresh Kamboju]

Hi Thomas,

On Thu, 3 Feb 2022 at 15:09, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>
> As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
> the option to fix the build failure. The error message is shown
> below.
>
>   arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
>     `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
>     `drm_panel_dp_aux_backlight'
>   make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
>
> The issue has been reported before, when DisplayPort helpers were
> hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
>
> v2:
>         * fix and expand commit description (Arnd)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Fixes: adb9d5a2cc77 ("drm/dp: Move DisplayPort helpers into separate helper module")
> Fixes: 5f04e7ce392d ("drm/panel-edp: Split eDP panels out of panel-simple")
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Link: https://lore.kernel.org/dri-devel/CA+G9fYvN0NyaVkRQmA1O6rX7H8PPaZrUAD7=RDy33QY9rUU-9g@mail.gmail.com/ # [1]
> Link: https://lore.kernel.org/all/20211117062704.14671-1-rdunlap@infradead.org/ # [2]
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: dri-devel@lists.freedesktop.org

Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>

This patch fixes the repored build problem.


> ---
>  drivers/gpu/drm/panel/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 434c2861bb40..0aec5a10b064 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -106,6 +106,7 @@ config DRM_PANEL_EDP
>         depends on PM
>         select VIDEOMODE_HELPERS
>         select DRM_DP_AUX_BUS
> +       select DRM_DP_HELPER
>         help
>           DRM panel driver for dumb eDP panels that need at most a regulator and
>           a GPIO to be powered up. Optionally a backlight can be attached so
> --
> 2.34.1
>


-- 
Linaro LKFT
https://lkft.linaro.org

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Geert Uytterhoeven]

Hi Thomas,

On Mon, Feb 7, 2022 at 12:31 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
> As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
> the option to fix the build failure. The error message is shown
> below.
>
>   arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
>     `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
>     `drm_panel_dp_aux_backlight'
>   make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
>
> The issue has been reported before, when DisplayPort helpers were
> hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
>
> v2:
>         * fix and expand commit description (Arnd)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Thanks for your patch!

This fixes the build errors I'm seeing, so
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Geert Uytterhoeven]

On Tue, Feb 8, 2022 at 10:39 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Mon, Feb 7, 2022 at 12:31 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
> > As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
> > the option to fix the build failure. The error message is shown
> > below.
> >
> >   arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
> >     `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
> >     `drm_panel_dp_aux_backlight'
> >   make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
> >
> > The issue has been reported before, when DisplayPort helpers were
> > hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
> >
> > v2:
> >         * fix and expand commit description (Arnd)
> >
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>
> Thanks for your patch!
>
> This fixes the build errors I'm seeing, so
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Is this planned to be queued? This is still failing in drm-next.
Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Doug Anderson]

Hi,

On Tue, Feb 22, 2022 at 1:31 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> On Tue, Feb 8, 2022 at 10:39 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Mon, Feb 7, 2022 at 12:31 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
> > > As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
> > > the option to fix the build failure. The error message is shown
> > > below.
> > >
> > >   arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
> > >     `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
> > >     `drm_panel_dp_aux_backlight'
> > >   make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
> > >
> > > The issue has been reported before, when DisplayPort helpers were
> > > hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
> > >
> > > v2:
> > >         * fix and expand commit description (Arnd)
> > >
> > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> >
> > Thanks for your patch!
> >
> > This fixes the build errors I'm seeing, so
> > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> Is this planned to be queued? This is still failing in drm-next.
> Thanks!

Looks like this has been in drm-misc-next since Feb 4:

---

commit eea89dff4c39a106f98d1cb5e4d626f8c63908b9
Author:     Thomas Zimmermann <tzimmermann@suse.de>
AuthorDate: Thu Feb 3 10:39:22 2022 +0100
Commit:     Thomas Zimmermann <tzimmermann@suse.de>
CommitDate: Fri Feb 4 09:38:47 2022 +0100

    drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

---

Maybe it needed to land elsewhere, though?

-Doug

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 2178 bytes --]

Hi

Am 23.02.22 um 17:11 schrieb Doug Anderson:
> Hi,
> 
> On Tue, Feb 22, 2022 at 1:31 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>>
>> On Tue, Feb 8, 2022 at 10:39 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>>> On Mon, Feb 7, 2022 at 12:31 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>>> As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
>>>> the option to fix the build failure. The error message is shown
>>>> below.
>>>>
>>>>    arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
>>>>      `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined reference to
>>>>      `drm_panel_dp_aux_backlight'
>>>>    make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
>>>>
>>>> The issue has been reported before, when DisplayPort helpers were
>>>> hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
>>>>
>>>> v2:
>>>>          * fix and expand commit description (Arnd)
>>>>
>>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>>
>>> Thanks for your patch!
>>>
>>> This fixes the build errors I'm seeing, so
>>> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>>
>> Is this planned to be queued? This is still failing in drm-next.
>> Thanks!
> 
> Looks like this has been in drm-misc-next since Feb 4:
> 
> ---
> 
> commit eea89dff4c39a106f98d1cb5e4d626f8c63908b9
> Author:     Thomas Zimmermann <tzimmermann@suse.de>
> AuthorDate: Thu Feb 3 10:39:22 2022 +0100
> Commit:     Thomas Zimmermann <tzimmermann@suse.de>
> CommitDate: Fri Feb 4 09:38:47 2022 +0100
> 
>      drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP
> 
> ---
> 
> Maybe it needed to land elsewhere, though?

Sorry about the mess. We had some confusion with this cycle's 
drm-misc-next pull request, which got delayed significantly. There's 
been a PR today, which should be merged into drm-next any time now. The 
patch will be part of that.

Best regards
Thomas

> 
> -Doug

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

Re: [PATCH v2] drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP

[Thorsten Leemhuis]

[CCing Dave and Daniel]

Hi, this is your Linux kernel regression tracker.

On 23.02.22 20:06, Thomas Zimmermann wrote:
> Am 23.02.22 um 17:11 schrieb Doug Anderson:
>> On Tue, Feb 22, 2022 at 1:31 AM Geert Uytterhoeven
>> <geert@linux-m68k.org> wrote:
>>> On Tue, Feb 8, 2022 at 10:39 AM Geert Uytterhoeven
>>> <geert@linux-m68k.org> wrote:
>>>> On Mon, Feb 7, 2022 at 12:31 PM Thomas Zimmermann
>>>> <tzimmermann@suse.de> wrote:
>>>>> As reported in [1], DRM_PANEL_EDP depends on DRM_DP_HELPER. Select
>>>>> the option to fix the build failure. The error message is shown
>>>>> below.
>>>>>
>>>>>    arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in
>>>>> function
>>>>>      `panel_edp_probe': panel-edp.c:(.text+0xb74): undefined
>>>>> reference to
>>>>>      `drm_panel_dp_aux_backlight'
>>>>>    make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
>>>>>
>>>>> The issue has been reported before, when DisplayPort helpers were
>>>>> hidden behind the option CONFIG_DRM_KMS_HELPER. [2]
>>>>>
>>>>> v2:
>>>>>          * fix and expand commit description (Arnd)
>>>>>
>>>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>>>
>>>> Thanks for your patch!
>>>>
>>>> This fixes the build errors I'm seeing, so
>>>> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>>>
>>> Is this planned to be queued? This is still failing in drm-next.
>>> Thanks!
>>
>> Looks like this has been in drm-misc-next since Feb 4:
>>
>> ---
>>
>> commit eea89dff4c39a106f98d1cb5e4d626f8c63908b9
>> Author:     Thomas Zimmermann <tzimmermann@suse.de>
>> AuthorDate: Thu Feb 3 10:39:22 2022 +0100
>> Commit:     Thomas Zimmermann <tzimmermann@suse.de>
>> CommitDate: Fri Feb 4 09:38:47 2022 +0100
>>
>>      drm/panel: Select DRM_DP_HELPER for DRM_PANEL_EDP
>>
>> ---
>>
>> Maybe it needed to land elsewhere, though?
> 
> Sorry about the mess. We had some confusion with this cycle's
> drm-misc-next pull request, which got delayed significantly. There's
> been a PR today, which should be merged into drm-next any time now. The
> patch will be part of that.

The patch for this regression late last week finally showed up in
linux-next, great. But:

I noticed the patch is not in drm-fixes but in drm-next -- and thus
afaics seems to be on tack to only get merged in the next merge window
(or am I wrong with that?). That seems wrong to me, as this fixes a
regression (albeit from the previous cycle, not from the current one)
and it already took quite a while to get this relative simple fix
finally on track -- but it's still far away from getting fixed in 5.16
and thus will make it into 5.17, too. That seems wrong to me, at least
if the risk is low (which is the case here afaics).

FWIW, this is not the only time where I noticed something like that,
that's why I wrote documentation that covers this which is on track to
get merged in the next merge window, unless Linus objects:

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/process/handling-regressions.rst#n131

To quote one of the sections relevant in this particular case:

>  * Aim to fix regressions within one week after the culprit was identified, if
>    the issue was introduced in either:
> 
>     * a recent stable/longterm release
> 
>     * the development cycle of the latest proper mainline release

Ciao, Thorsten