Re: [PATCH] drm/fb: Fix randconfig builds

[Jackie Liu <liu.yun@linux.dev>]

Hi Jani.

Your suggestion is that?

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 7ff89690a976..ba179a539497 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -77,6 +77,7 @@ config DRM_DEBUG_SELFTEST
  config DRM_KMS_HELPER
         tristate
         depends on DRM
+       depends on FB if DRM_FBDEV_EMULATION
         help
           CRTC helpers for KMS drivers.


But it has a syntax error.

--
Thanks, BR, Jackie Liu

在 2021/8/16 下午4:33, Jani Nikula 写道:
> On Mon, 16 Aug 2021, Jackie Liu <liu.yun@linux.dev> wrote:
>> Hi Jani.
>>
>> My CI report an randconfigs build failed. there are:
>>
>> drm_fb_helper.c:(.text+0x302): undefined reference to `fb_set_suspend'
>> drm_fb_helper.c:(.text+0xaea): undefined reference to `register_framebuffer'
>> drm_fb_helper.c:(.text+0x1dcc): undefined reference to `framebuffer_alloc'
>> ld: drm_fb_helper.c:(.text+0x1dea): undefined reference to `fb_alloc_cmap'
>> ld: drm_fb_helper.c:(.text+0x1e2f): undefined reference to `fb_dealloc_cmap'
>> ld: drm_fb_helper.c:(.text+0x1e5b): undefined reference to
>> `framebuffer_release'
>> drm_fb_helper.c:(.text+0x1e85): undefined reference to
>> `unregister_framebuffer'
>> drm_fb_helper.c:(.text+0x1ee9): undefined reference to `fb_dealloc_cmap'
>> ld: drm_fb_helper.c:(.text+0x1ef0): undefined reference to
>> `framebuffer_release'
>> drm_fb_helper.c:(.text+0x1f96): undefined reference to
>> `fb_deferred_io_cleanup'
>> drm_fb_helper.c:(.text+0x203b): undefined reference to `fb_sys_read'
>> drm_fb_helper.c:(.text+0x2051): undefined reference to `fb_sys_write'
>> drm_fb_helper.c:(.text+0x208d): undefined reference to `sys_fillrect'
>> drm_fb_helper.c:(.text+0x20bb): undefined reference to `sys_copyarea'
>> drm_fb_helper.c:(.text+0x20e9): undefined reference to `sys_imageblit'
>> drm_fb_helper.c:(.text+0x2117): undefined reference to `cfb_fillrect'
>> drm_fb_helper.c:(.text+0x2172): undefined reference to `cfb_copyarea'
>> drm_fb_helper.c:(.text+0x21cd): undefined reference to `cfb_imageblit'
>> drm_fb_helper.c:(.text+0x2233): undefined reference to `fb_set_suspend'
>> drm_fb_helper.c:(.text+0x22b0): undefined reference to `fb_set_suspend'
>> drm_fb_helper.c:(.text+0x250f): undefined reference to `fb_deferred_io_init'
>>
>> The main reason is because DRM_FBDEV_EMULATION is built-in, and
>> CONFIG_FB is compiled as a module.
> 
> DRM_FBDEV_EMULATION is not a module, it's just a config
> knob. drm_fb_helper.ko is the module, enabled via DRM_KMS_HELPER, and it
> has an implicit dependency on FB, and DRM_FBDEV_EMULATION selects
> DRM_KMS_HELPER. Select just breaks dependencies in all kinds of ways.
> 
> This might help in config DRM_KMS_HELPER, and it might help the reader
> because it's factual:
> 
> 	depends on FB if DRM_FBDEV_EMULATION
> 
> 
> BR,
> Jani.
> 
> 
> 
> 
> 
>>
>> --
>> Jackie Liu
>>
>> 在 2021/8/16 下午3:01, Jani Nikula 写道:
>>> On Mon, 16 Aug 2021, Jackie Liu <liu.yun@linux.dev> wrote:
>>>> From: Jackie Liu <liuyun01@kylinos.cn>
>>>>
>>>> When CONFIG_DRM_FBDEV_EMULATION is compiled to y and CONFIG_FB is m, the
>>>> compilation will fail. we need make that dependency explicit.
>>>
>>> What's the failure mode? Using select here is a bad idea.
>>>
>>> BR,
>>> Jani.
>>>
>>>>
>>>> Reported-by: k2ci <kernel-bot@kylinos.cn>
>>>> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
>>>> ---
>>>>    drivers/gpu/drm/Kconfig | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>>>> index 7ff89690a976..346a518b5119 100644
>>>> --- a/drivers/gpu/drm/Kconfig
>>>> +++ b/drivers/gpu/drm/Kconfig
>>>> @@ -98,7 +98,7 @@ config DRM_DEBUG_DP_MST_TOPOLOGY_REFS
>>>>    config DRM_FBDEV_EMULATION
>>>>    	bool "Enable legacy fbdev support for your modesetting driver"
>>>>    	depends on DRM
>>>> -	depends on FB
>>>> +	select FB
>>>>    	select DRM_KMS_HELPER
>>>>    	select FB_CFB_FILLRECT
>>>>    	select FB_CFB_COPYAREA
>>>
>