On Mon, May 15, 2023 at 10:17 AM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote: > Am 15.05.23 um 10:01 schrieb Linus Walleij: > > But the display is flickering like crazy so the updating frequency is > > totally off, which is because it does not scale down the resolution, > > the print used to be: > > > > Console: switching to colour frame buffer device 80x30 > > drm-clcd-pl111 c1000000.display: [drm] fb0: pl111drmfb frame buffer device > > > > It is now: > > > > Console: switching to colour frame buffer device 100x37 > > drm-clcd-pl111 c1000000.display: [drm] fb0: pl111drmfb frame buffer device > > > > 100x37! (i.e. 800x296), this display can only do 640x240. > > Any idea what else is going wrong here? Or is this another regression > > on top of the first regression ... I was under the impression that > > your change was only about formats not resolutions. > > If your display only supports 640x240, you should filter out all the > other modes in the driver, if necessary. To me, that seems fix-worthy in > any case. I think I found this, the bandwidth limit calculation in drivers/gpu/drm/pl111/pl111_display.c was using the bpp from the config and this was decreased from 16 to 15 and as it determined cpp by dividing bpp/8 this decreased from 2 bytes to 1 byte. Testing with DIV_ROUND_UP() in combination with the previous fix! Yours, Linus Walleij
