On Sat, Oct 24, 2020 at 12:52 AM Ville Syrjälä ville.syrjala@linux.intel.com wrote:
On Fri, Oct 23, 2020 at 10:03:50PM +0000, Simon Ser wrote:
On Friday, October 23, 2020 10:39 PM, Ville Syrjala ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
The code responsible for creating the IN_FORMATS blob is broken when the driver doesn't provide a .format_mod_supported() hook. It just copies in the format list, but leaves all the modifier information zeroed. That would indicate (in a very silly way) that there are in fact no supported format+modifier combinations. That is utter nonsense.
Should we WARN_ON when the driver enables allow_fb_modifiers but doesn't populate format_mod_supported?
.format_mod_supported() was supposed to be optional IIRC.
But now that I look at it, it looks like only these drivers are lacking .format_mod_supported(): exynos, mxsfb, tiny/cirrus, tiny/gm12u320.
There is some other oddity going on with sun4i which sometimes uses modifiers sometimes it doesn't. No idea what is going on there. But it does have .format_mod_supported() at least.
So I guess if we can get exynos, mxsfb, and tiny/* to implement the hook then we could make it mandatory.
I'd just delete it all, since it's obviously not tested for these drivers. And then add a patch which warns if allow_fb_modifiers, modifiers list passed y/n and .format_mod_support don't all agree. Since a bunch of your don't even set allow_fb_modifiers but pass a format list. So it's a complete mess :-/
Next step would then be to add some todo items, at least the simple/tiny drivers should all be able to do this fairly easily, and probably with linear only as the default. -Daniel