Re: [PATCH v1 2/2] drivers/gpu/drm: don't select DMA_CMA or CMA from aspeed or etnaviv

From: David Hildenbrand <david@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>, Linus Walleij <linus.walleij@linaro.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, Joel Stanley <joel@jms.id.au>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Andrew Jeffery <andrew@aj.id.au>,
	Lucas Stach <l.stach@pengutronix.de>,
	Russell King <linux+etnaviv@armlinux.org.uk>,
	Christian Gmeiner <christian.gmeiner@gmail.com>,
	Mike Rapoport <rppt@kernel.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Peter Collingbourne <pcc@google.com>,
	linux-aspeed <linux-aspeed@lists.ozlabs.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	The etnaviv authors <etnaviv@lists.freedesktop.org>,
	Linux Fbdev development list <linux-fbdev@vger.kernel.org>
Subject: Re: [PATCH v1 2/2] drivers/gpu/drm: don't select DMA_CMA or CMA from aspeed or etnaviv
Date: Fri, 9 Apr 2021 10:07:01 +0200	[thread overview]
Message-ID: <e6fa1b72-24ca-28bc-0115-7ceceb101e96@redhat.com> (raw)
In-Reply-To: <CAK8P3a2Wu7tT-YajfdXSSVvg5MYMEnEy3APJ83DcLeJdGkkSrQ@mail.gmail.com>

On 08.04.21 15:19, Arnd Bergmann wrote:
> On Thu, Apr 8, 2021 at 2:50 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>>
>> On Thu, Apr 8, 2021 at 2:01 PM David Hildenbrand <david@redhat.com> wrote:
>>
>>>> This is something you could do using a hidden helper symbol like
>>>>
>>>> config DRMA_ASPEED_GFX
>>>>          bool "Aspeed display driver"
>>>>          select DRM_WANT_CMA
>>>>
>>>> config DRM_WANT_CMA
>>>>          bool
>>>>          help
>>>>             Select this from any driver that benefits from CMA being enabled
>>>>
>>>> config DMA_CMA
>>>>          bool "Use CMA helpers for DRM"
>>>>          default DRM_WANT_CMA
>>>>
>>>>            Arnd
>>>>
>>>
>>> That's precisely what I had first, with an additional "WANT_CMA" --  but
>>> looking at the number of such existing options (I was able to spot 1 !)
>>
>> If you do this it probably makes sense to fix a few other drivers
>> Kconfig in the process. It's not just a problem with your driver.
>> "my" drivers:
>>
>> drivers/gpu/drm/mcde/Kconfig
>> drivers/gpu/drm/pl111/Kconfig
>> drivers/gpu/drm/tve200/Kconfig
>>
>> certainly needs this as well, and pretty much anything that is
>> selecting DRM_KMS_CMA_HELPER or
>> DRM_GEM_CMA_HELPER "wants" DMA_CMA.
> 
> Are there any that don't select either of the helpers and
> still want CMA? If not, it would be easy to just add
> 
>     default  DRM_KMS_CMA_HELPER || DRM_GEM_CMA_HELPER
> 
> and skipt the extra symbol.

That sounds like a reasonable thing to do. I'll look into that.

-- 
Thanks,

David / dhildenb