Re: [PATCH 5/6] drm/fb-helper: Consolidate CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM

[Maxime Ripard <maxime@cerno.tech>]

On Fri, Mar 17, 2023 at 01:51:42PM +0100, Thomas Zimmermann wrote:
> Hi
> 
> Am 17.03.23 um 13:39 schrieb Javier Martinez Canillas:
> > Thomas Zimmermann <tzimmermann@suse.de> writes:
> > 
> > > Consolidate all handling of CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM by
> > > making the module parameter optional in drm_fb_helper.c.
> > > 
> > > Without the config option, modules can set smem_start in struct
> > > fb_info for internal usage, but not export if to userspace. The
> > > address can only be exported by enabling the option and setting
> > > the module parameter. Also update the comment.
> > > 
> > 
> > I was going to ask at what point we could just get rid of this Kconfig
> > symbol since it already depends on EXPERT anyways so most distros will
> > not enable it.
> > 
> > But I looked then and noticed that it was added just a few years ago in
> > commit 4be9bd10e22d "(drm/fb_helper: Allow leaking fbdev smem_start"),
> > so it seems that people still need that :(
> 
> I don't even know which userspace drivers need this symbol. Probably
> something on Android.

At least the Mali (utgard) user-space stack uses it, including on
"regular" distributions.

I don't know about newest Mali generations.

Maxime