[RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

[Jani Nikula]

On Tue, 10 Mar 2015, Archit Taneja <architt at codeaurora.org> wrote:
> On 03/10/2015 03:35 PM, Daniel Vetter wrote:
>> On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
>>>
>>>
>>> On 03/10/2015 03:17 PM, Daniel Vetter wrote:
>>>> On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
>>> DRM_KMS_FB_HELPER selects that for us, right?
>>
>> Hm right I've missed that. Reminds me that you need one more patch at the
>> end to remove all the various select DRM_KMS_FB_HELPER from all drm
>> drivers. Otherwise this knob here won't work by default if you e.g. select
>> radeon. In general we can't mix explicit options with menu entries with a
>> select.
>
> I was trying that out. Removing DRM_KMS_FB_HELPER and having 
> DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
> internally in their respective xyz_fbdev.c files.
>
> Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers 
> and replace them with 'select DRM_FBDEV_EMULATION'?

Slightly tangential: As a rule of thumb, you should not "select"
anything that is visible in menuconfig or has dependencies [1]. This
will break the build eventually, and attempts to fix it are troublesome
[2].

BR,
Jani.

[1] Documentation/kbuild/kconfig-language.txt
[2] http://mid.gmane.org/1413580403-16225-1-git-send-email-jani.nikula@intel.com


-- 
Jani Nikula, Intel Open Source Technology Center