Re: gpu: drm_fb_cma_helper.c:46: undefined reference to `drm_gem_fb_get_obj'

From: Thomas Zimmermann <tzimmermann@suse.de>
To: Arnd Bergmann <arnd@arndb.de>, Randy Dunlap <rdunlap@infradead.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	open list <linux-kernel@vger.kernel.org>,
	Linux-Next Mailing List <linux-next@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: gpu: drm_fb_cma_helper.c:46: undefined reference to `drm_gem_fb_get_obj'
Date: Wed, 27 Oct 2021 10:08:03 +0200	[thread overview]
Message-ID: <109f764d-60fe-0ae5-ddd4-760210e4992a@suse.de> (raw)
In-Reply-To: <CAK8P3a3v9mb8RH7ER=iF2SAizv-Sb=hTWzpuQzL050ToR02h+Q@mail.gmail.com>

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Hi!

Am 27.10.21 um 08:50 schrieb Arnd Bergmann:
> On Wed, Oct 27, 2021 at 8:26 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>> On 10/26/21 11:19 PM, Arnd Bergmann wrote:
>>> On Wed, Oct 27, 2021 at 2:58 AM Randy Dunlap <rdunlap@infradead.org> wrote:
> 
>>> This trivial change makes it all build:
>>>
>>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>>> index c08860db2520..699f434ce813 100644
>>> --- a/drivers/gpu/drm/Kconfig
>>> +++ b/drivers/gpu/drm/Kconfig
>>> @@ -218,7 +218,7 @@ config DRM_GEM_CMA_HELPER
>>>             Choose this if you need the GEM CMA helper functions
>>>
>>>    config
> 
>>> -       bool
>>> +       tristate
>>>           depends on DRM
>>>           select DRM_GEM_CMA_HELPER
>>>           help
>>>
>>> but this needs some more testing to make sure it doesn't add
>>> any other regressions.
>>>
>>> Interestingly, I never hit the problem in randconfig testing since
>>> there is always some '=y' driver that selects DRM_KMS_HELPER.
>>
>> Thomas had posted a patch that also fixes the problem.
>> Somehow I missed seeing that the first time around.
> 
> Ah right, I missed that as well. That patch seems reasonable
> to me, but I think we may want both of them in this case, as
> it does not address DRM_GEM_CMA_HELPER being set to =y
> when it is only used from modules.

Yes, the bool state was indeed the problem. The patch I posted resolves 
the issue for now. For later, I have a patchset that improves CMA helper 
usage a bit and resolves the Kconfig problem.

Best regards
Thomas

> 
>         Arnd
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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