On Tue, Aug 31, 2021 at 7:19 PM Geert Uytterhoeven [off-list ref] wrote:

Hi Handa-san,

On Tue, Aug 31, 2021 at 5:24 PM Tetsuo Handa
[off-list ref] wrote:

quoted

On 2021/08/31 15:48, Geert Uytterhoeven wrote:

quoted

Furthermore, this restricts the virtual frame buffer size on 64-bit,
too, while graphics cards can have much more than 4 GiB of RAM.

Excuse me, but do you mean that some hardware allows allocating more than
UINT_MAX bytes of memory for kernel frame buffer drivers?

While smem_len is u32 (there have been complaints about such
limitations on 64-bit platforms as far as 10 years ago), I see no
reason why a graphics card with more than 4 GiB of RAM would not be
able to provide a very large virtual screen.

Of course e.g. vga16fb cannot, as it is limited to 64 KiB.

The first gpus with 4GB or more memory started shipping in 2012. We're
not going to have fbdev drivers for these, so let's not invent code
for use-cases that aren't please.

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch