[Letux-kernel] Fixing TILER

H. Nikolaus Schaller hns at goldelico.com
Sun Nov 4 20:04:42 CET 2018


> Am 04.11.2018 um 18:46 schrieb Matthijs van Duin <matthijsvanduin at gmail.com>:
> 
> On Sat, 3 Nov 2018 at 07:51, Matthijs van Duin
> <matthijsvanduin at gmail.com> wrote:
>>> if (rotation != DRM_MODE_ROTATE_180 || !plane->rotation_property) {
>>> fb_helper->sw_rotations |= rotation;
>>> return;
>>> }
>>> 
>>> which makes me think that this code indeed disables hardware rotation for /dev/fb0.
>> 
>> No, plane->rotation_property != NULL, so it should not use software rotation.
> 
> D'oh, I misread that. This will indeed need to be fixed to support
> 90/270 degree rotation.
> 
> We should definitely arrange for the panel orientation to be declared
> properly now that there's a mechanism for it, instead of the hack with
> a kernel parameter.

Agreed.

> This doesn't require any of the "orientation
> quirks" stuff, you can also set
> connector->display_info.panel_orientation and then call
> drm_connector_init_panel_orientation_property(connector, 0, 0).

The question is how and where this should be called.

Ideally this panel orientation parameter should not even be any "orientation quirks"
or kernel parameter. It should be a property of either the display controller or
the panel in the device tree.

Maybe the best next steps would be to discuss this with Hans de Goede
and Tomi Valkainen. To get the patches upstream.

Would you want to do this yourself or should I take the lead of editing
and sending patches (and you jumping into the discussion for details I
can't explain)?

> 
> Although, I suppose it might be nice for testing purposes to add an
> orientation quirk that obtains its value from a kernel parameter.

Indeed. That is why I kept the parameter (+ tiler-ctl tool) for the
moment.

BR and thanks,
Nikolaus



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