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

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

在 2021/8/16 下午4:56, Jani Nikula 写道:
> On Mon, 16 Aug 2021, Jani Nikula <jani.nikula@linux.intel.com> wrote:
>> On Mon, 16 Aug 2021, Jackie Liu <liu.yun@linux.dev> wrote:
>>> 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.
>>
>> Ah, try this then:
>>
>> 	depends on FB || FB=n
> 
> Or this monster:
> 
> 	depends on FB || DRM_FBDEV_EMULATION=n


Hi Jani,

    depends on FB || DRM_FBDEV_EMULATION=n Will cause the following
warnings.

WARNING: unmet direct dependencies detected for DRM_KMS_HELPER
   Depends on [m]: HAS_IOMEM [=y] && DRM [=y] && (FB [=m] || 
!DRM_FBDEV_EMULATION [=y])
   Selected by [y]:
   - DRM_DEBUG_SELFTEST [=y] && HAS_IOMEM [=y] && DRM [=y] && 
DEBUG_KERNEL [=y]
   - DRM_VKMS [=y] && HAS_IOMEM [=y] && DRM [=y]
   - TINYDRM_ILI9341 [=y] && HAS_IOMEM [=y] && DRM [=y] && SPI [=y]
   - TINYDRM_MI0283QT [=y] && HAS_IOMEM [=y] && DRM [=y] && SPI [=y]
   - TINYDRM_ST7586 [=y] && HAS_IOMEM [=y] && DRM [=y] && SPI [=y]
   - TINYDRM_ST7735R [=y] && HAS_IOMEM [=y] && DRM [=y] && SPI [=y]
   - DRM_ANALOGIX_ANX78XX [=y] && HAS_IOMEM [=y] && DRM [=y] && 
DRM_BRIDGE [=y]
   Selected by [m]:
   - DRM_FBDEV_EMULATION [=y] && HAS_IOMEM [=y] && DRM [=y] && FB [=m]
   - DRM_SIMPLEDRM [=m] && HAS_IOMEM [=y] && DRM [=y]
   - TINYDRM_HX8357D [=m] && HAS_IOMEM [=y] && DRM [=y] && SPI [=y]
   - TINYDRM_REPAPER [=m] && HAS_IOMEM [=y] && DRM [=y] && SPI [=y]
configuration written to .config

How about this?

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 7ff89690a976..797eeea9cbbe 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -98,8 +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 DRM_KMS_HELPER
+       depends on (FB=y && DRM_KMS_HELPER) || (FB=m && DRM_KMS_HELPER=m)
         select FB_CFB_FILLRECT
         select FB_CFB_COPYAREA
         select FB_CFB_IMAGEBLIT


--
BR, Jackie Liu

> 
> 
>>
>>>
>>> --
>>> 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
>>>>>>
>>>>
>