Re: [Freedreno] [PATCH] drm/msm: Make DRM_MSM default to 'm'

From: Rob Clark <robdclark@gmail.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Jordan Crouse <jcrouse@codeaurora.org>,
	freedreno <freedreno@lists.freedesktop.org>,
	David Airlie <airlied@linux.ie>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Sean Paul <sean@poorly.run>
Subject: Re: [Freedreno] [PATCH] drm/msm: Make DRM_MSM default to 'm'
Date: Wed, 7 Aug 2019 11:08:53 -0700	[thread overview]
Message-ID: <CAF6AEGv6EY5UBYF8D9tuSaMDvkdrBt+zvRxQA+V4PG6ZfKhUAg@mail.gmail.com> (raw)
In-Reply-To: <20190807173838.GB30025@ravnborg.org>

On Wed, Aug 7, 2019 at 10:38 AM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Jordan.
> On Wed, Aug 07, 2019 at 11:24:27AM -0600, Jordan Crouse wrote:
> > Most use cases for DRM_MSM will prefer to build both DRM and MSM_DRM as
> > modules but there are some cases where DRM might be built in for whatever
> > reason and in those situations it is preferable to still keep MSM as a
> > module by default and let the user decide if they _really_ want to build
> > it in.
> >
> > Additionally select QCOM_COMMAND_DB for ARCH_QCOM targets to make sure
> > it doesn't get missed when we need it for a6xx tarets.
> >
> > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> > ---
> >
> >  drivers/gpu/drm/msm/Kconfig | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
> > index 9c37e4d..3b2334b 100644
> > --- a/drivers/gpu/drm/msm/Kconfig
> > +++ b/drivers/gpu/drm/msm/Kconfig
> > @@ -14,11 +14,12 @@ config DRM_MSM
> >       select SHMEM
> >       select TMPFS
> >       select QCOM_SCM if ARCH_QCOM
> > +     select QCOM_COMMAND_DB if ARCH_QCOM
> >       select WANT_DEV_COREDUMP
> >       select SND_SOC_HDMI_CODEC if SND_SOC
> >       select SYNC_FILE
> >       select PM_OPP
> > -     default y
> > +     default m
>
> As a general comment the right thing would be to drop this default.
> As it is now the Kconfig says that when DRM is selected then all of the
> world would then also get DRM_MSM, which only a small part of this world
> you see any benefit in.
> So they now have to de-select MSM.

If the default is dropped, it should probably be accompanied by adding
CONFIG_DRM_MSM=m to defconfig's, I think

BR,
-R

> Kconfig has:
>     depends on ARCH_QCOM || SOC_IMX5 || (ARM && COMPILE_TEST)
>
> So maybe not all of the world but all QCOM or IMX5 users. Maybe they are all
> interested in MSM. Otherwise the default should rather be dropped.
> If there is any good hints then the help text could anyway use some
> love, and then add the info there.
>
> The other change with QCOM_COMMAND_DB seems on the other hand to make
> sense but then this is another patch.
>
>         Sam
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