On 12/04/2023 17:13, Javier Martinez Canillas wrote:
Jocelyn Falempe <jfalempe@xxxxxxxxxx> writes:
The bandwidth between system memory and VRAM is very limited
on G200.
So when using a 32bit framebuffer on system memory, convert it to 24bit
when copying the frame to the VRAM, this allows to go 33% faster.
Converting the format on the fly is negligible, even on low end CPU.
small benchmark on my Dell T310:
1280x1024 32bits: ~125ms to transfert a single frame.
1280x1024 24bits: ~95ms
Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
---
I assume that the alpha channel is unused on this display HW and is just
exposed to user-space to make the DRM driver more compatible ?
Yes, alpha channel is dropped by the hardware, and has no impact on the
display.
Most userspace now prefer 32bit framebuffer. I know Gnome/wayland
default to 32bit, and probably other DE are doing the same.
If so, probably has to be mentioned in the changelog but other than that:
ok I will add this in the commit message.
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Thanks,
--
Jocelyn
