Hello Kieran,
On 11/3/22 11:59, Kieran Bingham wrote:
> Hi Randy,
>
> Quoting Randy Dunlap (2022-11-03 06:06:45)
>> ping. I have verified (on linux-next-20221103) that this is still needed.
>> Thanks.
>>
>> On 10/18/22 11:18, Randy Dunlap wrote:
>>> When CONFIG_DRM_RCAR_DU=y and CONFIG_DRM_RCAR_MIPI_DSI=m, calls
>>> from the builtin driver to the mipi driver fail due to linker
>>> errors.
>>> Since the RCAR_MIPI_DSI driver is not always required, fix the
>>> build error by making DRM_RCAR_DU optionally depend on the
>>> RCAR_MIPI_DSI Kconfig symbol. This prevents the problematic
>>> kconfig combination without requiring that RCAR_MIPI_DSI always
>>> be enabled.
>>>
>>> aarch64-linux-ld: drivers/gpu/drm/rcar-du/rcar_du_crtc.o: in function `rcar_du_crtc_atomic_enable':
>>> rcar_du_crtc.c:(.text+0x3a18): undefined reference to `rcar_mipi_dsi_pclk_enable'
>>> aarch64-linux-ld: drivers/gpu/drm/rcar-du/rcar_du_crtc.o: in function `rcar_du_crtc_atomic_disable':
>>> rcar_du_crtc.c:(.text+0x47cc): undefined reference to `rcar_mipi_dsi_pclk_disable'
>>>
>>> Fixes: 957fe62d7d15 ("drm: rcar-du: Fix DSI enable & disable sequence")
>>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>>> Cc: Tomi Valkeinen <tomi.valkeinen+renesas@xxxxxxxxxxxxxxxx>
>>> Cc: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
>>> Cc: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
>>> Cc: LUU HOAI <hoai.luu.ub@xxxxxxxxxxx>
>>> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
>>> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
>>> Cc: David Airlie <airlied@xxxxxxxxx>
>>> Cc: Daniel Vetter <daniel@xxxxxxxx>
>>> ---
>>> drivers/gpu/drm/rcar-du/Kconfig | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff -- a/drivers/gpu/drm/rcar-du/Kconfig b/drivers/gpu/drm/rcar-du/Kconfig
>>> --- a/drivers/gpu/drm/rcar-du/Kconfig
>>> +++ b/drivers/gpu/drm/rcar-du/Kconfig
>>> @@ -4,6 +4,7 @@ config DRM_RCAR_DU
>>> depends on DRM && OF
>>> depends on ARM || ARM64
>>> depends on ARCH_RENESAS || COMPILE_TEST
>>> + depends on DRM_RCAR_MIPI_DSI || DRM_RCAR_MIPI_DSI=n
>
> Please forgive my ignorance, but I don't understand how this works.
> Could you explain what this is doing please?
>
> I know you've explained above that it fixes it to optionally depend on
> DRM_RCAR_MIPI_DSI ... but it's not making sense to me.
>
> To me - this is saying we depend on DRM_RCAR_MIPI_DSI being enabled, or
> not being enabled ... ? Which is like saying if (0 || 1) ?
>
> I'm guessing I'm missing something obvious :-S
>
What this Kconfig expression is saying is that it depends on DRM_RCAR_MIPI_DSI=y
if DRM_RCAR_DU=y and DRM_RCAR_MIPI_DSI=m if DRM_RCAR_DU=m. But that the it can
also be satisfied if is not set DRM_RCAR_MIPI_DSI.
This is usually used to make sure that you don't end with a configuration where
DRM_RCAR_MIPI_DSI=y and DRM_RCAR_DU=m or DRM_RCAR_MIPI_DSI=m and DRM_RCAR_DU=y.
Randy, I think that it's more idiomatic though to it express as following:
depends on DRM_RCAR_MIPI_DSI || !DRM_RCAR_MIPI_DSI
--
Best regards,
Javier Martinez Canillas
Core Platforms
Red Hat
