Hi Sam,
Le dim., juil. 3 2022 at 08:43:37 +0200, Sam Ravnborg sam@ravnborg.org a écrit :
Hi Paul,
On Sun, Jul 03, 2022 at 12:07:27AM +0100, Paul Cercueil wrote:
Until now, when running at the maximum resolution of 1280x720 at 32bpp on the JZ4770 SoC the output was garbled, the X/Y position of the top-left corner of the framebuffer warping to a random position with the whole image being offset accordingly, every time a new frame was being submitted.
This problem can be eliminated by using a bigger burst size for the DMA.
Are there any alignment constraints of the framebuffer that depends on the burst size? I am hit by this with some atmel IP - which is why I ask.
I would think that the framebuffer needs to be aligned with the burst size, indeed. Here, our buffers are always page-aligned so that's not a problem.
Patch looks good and is a-b.
Thanks!
Cheers, -Paul
Set in each soc_info structure the maximum burst size supported by the corresponding SoC, and use it in the driver.
Set the new value using regmap_update_bits() instead of regmap_set_bits(), since we do want to override the old value of the burst size. (Note that regmap_set_bits() wasn't really valid before for the same reason, but it never seemed to be a problem).
Cc: stable@vger.kernel.org Fixes: 90b86fcc47b4 ("DRM: Add KMS driver for the Ingenic JZ47xx SoCs") Signed-off-by: Paul Cercueil paul@crapouillou.net
Acked-by: Sam Ravnborg sam@ravnborg.org