* [PATCH] drm/panel-edp: modify Kconfig to prevent build error
@ 2021-11-17 6:27 Randy Dunlap
2021-11-17 7:58 ` Arnd Bergmann
0 siblings, 1 reply; 3+ messages in thread
From: Randy Dunlap @ 2021-11-17 6:27 UTC (permalink / raw)
To: linux-kernel
Cc: Randy Dunlap, kernel test robot, Arnd Bergmann, Daniel Vetter,
Javier Martinez Canillas, Sam Ravnborg, Douglas Anderson,
Linus Walleij, Thierry Reding, dri-devel
When CONFIG_DRM_KMS_HELPER=m and CONFIG_DRM_PANEL_EDP=y,
there is a build error in gpu/drm/panel/panel-edp.o:
arm-linux-gnueabi-ld: drivers/gpu/drm/panel/panel-edp.o: in function `panel_edp_probe':
panel-edp.c:(.text+0xf38): undefined reference to `drm_panel_dp_aux_backlight'
Fix this by limiting DRM_PANEL_DEP by the value of the DRM_KMS_HELPER
symbol.
Fixes: 5f04e7ce392d ("drm/panel-edp: Split eDP panels out of panel-simple")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: dri-devel@lists.freedesktop.org
---
drivers/gpu/drm/panel/Kconfig | 1 +
1 file changed, 1 insertion(+)
--- linux-next-20211117.orig/drivers/gpu/drm/panel/Kconfig
+++ linux-next-20211117/drivers/gpu/drm/panel/Kconfig
@@ -104,6 +104,7 @@ config DRM_PANEL_EDP
depends on OF
depends on BACKLIGHT_CLASS_DEVICE
depends on PM
+ depends on DRM_KMS_HELPER
select VIDEOMODE_HELPERS
select DRM_DP_AUX_BUS
help
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/panel-edp: modify Kconfig to prevent build error
2021-11-17 6:27 [PATCH] drm/panel-edp: modify Kconfig to prevent build error Randy Dunlap
@ 2021-11-17 7:58 ` Arnd Bergmann
2021-11-17 20:04 ` Randy Dunlap
0 siblings, 1 reply; 3+ messages in thread
From: Arnd Bergmann @ 2021-11-17 7:58 UTC (permalink / raw)
To: Randy Dunlap
Cc: Linux Kernel Mailing List, kernel test robot, Arnd Bergmann,
Daniel Vetter, Javier Martinez Canillas, Sam Ravnborg,
Douglas Anderson, Linus Walleij, Thierry Reding, dri-devel
On Wed, Nov 17, 2021 at 7:27 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> When CONFIG_DRM_KMS_HELPER=m and CONFIG_DRM_PANEL_EDP=y,
> there is a build error in gpu/drm/panel/panel-edp.o:
>
> arm-linux-gnueabi-ld: drivers/gpu/drm/panel/panel-edp.o: in function `panel_edp_probe':
> panel-edp.c:(.text+0xf38): undefined reference to `drm_panel_dp_aux_backlight'
>
> Fix this by limiting DRM_PANEL_DEP by the value of the DRM_KMS_HELPER
> symbol.
I think the analysis is correct, but this is not the correct fix since
DRM_KMS_HELPER
is not user-selectable. (Almost) all other drivers that rely on DRM_KMS_HELPER
use 'select' for this, and mixing the two risks running into circular
dependencies.
I see that there are already some 'depends on DRM_KMS_HELPER' in bridge
and panel drivers, so it's possible that we have to fix them all at the same to
do this right. I ran into another problem like this the other day and
I'm currently
testing with the patch below, but I have not posted that yet since I am not
fully convinced that this is the correct fix either.
Arnd
---
commit a836092fedaac66af03ea9ed7cb13214fd2ab8a2
Author: Arnd Bergmann <arnd@arndb.de>
Date: Mon Nov 15 16:54:04 2021 +0100
drm/mipi-dbi: select CONFIG_DRM_KMS_HELPER
The driver fails to build when the KMS helpers are disabled:
ld.lld: error: undefined symbol: drm_gem_fb_get_obj
>>> referenced by drm_mipi_dbi.c
>>> gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in
archive drivers/built-in.a
>>> referenced by drm_mipi_dbi.c
>>> gpu/drm/drm_mipi_dbi.o:(mipi_dbi_fb_dirty) in
archive drivers/built-in.a
ld.lld: error: undefined symbol: drm_gem_fb_begin_cpu_access
>>> referenced by drm_mipi_dbi.c
>>> gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in
archive drivers/built-in.a
ld.lld: error: undefined symbol: drm_fb_swab
>>> referenced by drm_mipi_dbi.c
>>> gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in
archive drivers/built-in.a
ld.lld: error: undefined symbol: drm_fb_xrgb8888_to_rgb565
>>> referenced by drm_mipi_dbi.c
>>> gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in
archive drivers/built-in.a
ld.lld: error: undefined symbol: drm_fb_memcpy
>>> referenced by drm_mipi_dbi.c
>>> gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in
archive drivers/built-in.a
This is fairly hard to hit in randconfig drivers, but it eventually
did trigger for me in a configuration where all other DRM drivers
are loadable modules, but DRM_PANEL_WIDECHIPS_WS2401 was built-in.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0039df26854b..a03c2761c5f9 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -29,6 +29,7 @@ menuconfig DRM
config DRM_MIPI_DBI
tristate
+ select DRM_KMS_HELPER
depends on DRM
config DRM_MIPI_DSI
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 431b6e12a81f..17a8d603e7d8 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -8,7 +8,6 @@ config DRM_BRIDGE
config DRM_PANEL_BRIDGE
def_bool y
depends on DRM_BRIDGE
- depends on DRM_KMS_HELPER
select DRM_PANEL
help
DRM bridge wrapper of DRM panels
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index cfc8d644cedf..40ec20f3552d 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -140,9 +140,8 @@ config DRM_PANEL_ILITEK_IL9322
config DRM_PANEL_ILITEK_ILI9341
tristate "Ilitek ILI9341 240x320 QVGA panels"
depends on OF && SPI
- depends on DRM_KMS_HELPER
- depends on DRM_KMS_CMA_HELPER
depends on BACKLIGHT_CLASS_DEVICE
+ select DRM_KMS_CMA_HELPER
select DRM_MIPI_DBI
help
Say Y here if you want to enable support for Ilitek IL9341
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/panel-edp: modify Kconfig to prevent build error
2021-11-17 7:58 ` Arnd Bergmann
@ 2021-11-17 20:04 ` Randy Dunlap
0 siblings, 0 replies; 3+ messages in thread
From: Randy Dunlap @ 2021-11-17 20:04 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Linux Kernel Mailing List, kernel test robot, Daniel Vetter,
Javier Martinez Canillas, Sam Ravnborg, Douglas Anderson,
Linus Walleij, Thierry Reding, dri-devel
On 11/16/21 11:58 PM, Arnd Bergmann wrote:
> On Wed, Nov 17, 2021 at 7:27 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>>
>> When CONFIG_DRM_KMS_HELPER=m and CONFIG_DRM_PANEL_EDP=y,
>> there is a build error in gpu/drm/panel/panel-edp.o:
>>
>> arm-linux-gnueabi-ld: drivers/gpu/drm/panel/panel-edp.o: in function `panel_edp_probe':
>> panel-edp.c:(.text+0xf38): undefined reference to `drm_panel_dp_aux_backlight'
>>
>> Fix this by limiting DRM_PANEL_DEP by the value of the DRM_KMS_HELPER
>> symbol.
>
> I think the analysis is correct, but this is not the correct fix since
> DRM_KMS_HELPER
> is not user-selectable. (Almost) all other drivers that rely on DRM_KMS_HELPER
> use 'select' for this, and mixing the two risks running into circular
> dependencies.
Oops. Thanks for catching that.
My first (local) version of the patch used select, but that got me
into kconfig circular dependency chain land (ugly).
Maybe your all-at-once patch can take care of that problem.
>
> I see that there are already some 'depends on DRM_KMS_HELPER' in bridge
> and panel drivers, so it's possible that we have to fix them all at the same to
> do this right. I ran into another problem like this the other day and
> I'm currently
> testing with the patch below, but I have not posted that yet since I am not
> fully convinced that this is the correct fix either.
I'll test some with it also.
thanks.
--
~Randy
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-11-17 6:27 [PATCH] drm/panel-edp: modify Kconfig to prevent build error Randy Dunlap
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2021-11-17 20:04 ` Randy Dunlap
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