Re: [PATCH 1/3] drm: mxsfb: Change driver.name to mxsfb-drm

[Leonard Crestez <leonard.crestez@nxp.com>]

On Thu, 2018-07-12 at 11:21 +0200, Stefan Agner wrote:
> On 10.07.2018 11:11, Marek Vasut wrote:
> > On 07/10/2018 11:06 AM, Stefan Agner wrote:
> > > This is one of the situation where states quo is kinda the worst
> > > situation.
> > > 
> > > Currently imx_v6_v7_defconfig and mxs_defconfig actually still uses
> > > CONFIG_FB_MXS.
> > > 
> > > I understand that you'd rather prefer to move forward. I suggest we do
> > > it in steps.
> > > 
> > > In 4.19:
> > > 
> > > - Change DRM driver.name to mxsfb-drm so we avoid conflicts for now
> > 
> > But this will break mesa if it depends on mxsfb name for ie. etnaviv
> > binding.
> 
> Does it? grep -r -e mxsfb in libdrm and mesa master returns nothing.
> 
> There is also .name in struct drm_driver, which is already set to
> mxsfb-drm... Is that the one exposed to user space?

Running etnaviv+x11 with a renamed mxsfb driver works fine on imx6sx-
sdb.

Tools like modetest already need -M mxsfb-drm, the drm_driver.name
seems to be what matters.

> - Remove CONFIG_FB_MXS from imx_v6_v7_defconfig/mxs_defconfig now, and
> only enable CONFIG_DRM_MXSFB=y

If one of the drivers is renamed then they can coexist: since the
bindings are distinct one driver will return a probe error and the
other will bind successfully. This can even be adjusted so that it
doesn't even print ugly scary errors.

This can last until somebody implements support for old bindings in the
drm driver and then FB_MXS can just be deleted.