[PATCH 00/26] x86: video: Speed up the framebuffer

Bin Meng
2020-05-22T15:29:57Z

Hi Simon,

On Wed, May 20, 2020 at 7:11 AM Simon Glass <sjg@chromium.org> wrote:
>
> Some architectures use a cached framebuffer and flush the cache as needed
> so that changes are visible. This is supported by U-Boot.
>
> However x86 uses an uncached framebuffer with a 'write-combining' feature
> to speed up writes. Reads are permitted but they are extremely expensive.
>

Is it possible to use cached framebuffer on x86?

> Unfortunately, reading from the frame buffer is quite common, e.g. to
> scroll it. This makes scrolling very slow.
>
> This series adds a new feature which supports copying modified parts of
> the frame buffer to the uncached hardware buffer. This speeds up scrolling
> dramatically on x86 so the extra complexity cost seems worth it.
>
> In an extreme case, the time to print the environment on minnowboard with
> 1280x1024 and CONFIG_CONSOLE_SCROLL_LINES disabled is reduced
> significantly, from 13 seconds to 300ms.
>

Thanks for the series. The improvements sounds great! I will get one
minnowmax board to test this series soon.

Regards,
Bin