On 2016-01-04 12:14, Alex Deucher wrote:

On Mon, Jan 4, 2016 at 12:57 PM, Jay Cornwall jay@jcornwall.me wrote:

...

Hi,

dce4_crtc_do_set_base is the only location in which EVERGREEN_GRPH_CONTROL is updated. This currently configures a non-tiled framebuffer on my SI system.

This design prevents drmModePageFlip from handling a framebuffer with a different tiling configuration.

Is this the intended architecture? i.e. All surfaces provided to drmModePageFlip should match the initial framebuffer layout, or should EVERGREEN_GRPH_CONTROL be updated on every page flip?

Pageflipping is only available between surfaces of the same format (i.e., we only update the base address, not the other parameters).

Thanks, I got it now. KWin/Wayland is only calling drmModeSetCrtc when the buffer stride changes, but flipping once from a dumb buffer to a GBM buffer.

I've filed: https://bugs.kde.org/show_bug.cgi?id=357543