On 3/24/22 12:18, Thomas Zimmermann wrote:

Hi

Am 24.03.22 um 20:11 schrieb Guenter Roeck:

quoted

Hi,

On Wed, Feb 23, 2022 at 08:38:03PM +0100, Thomas Zimmermann wrote:

quoted

Improve the performance of cfb_imageblit() by manually unrolling
the inner blitting loop and moving some invariants out. The compiler
failed to do this automatically. This change keeps cfb_imageblit()
in sync with sys_imagebit().

A microbenchmark measures the average number of CPU cycles
for cfb_imageblit() after a stabilizing period of a few minutes
(i7-4790, FullHD, simpledrm, kernel with debugging).

cfb_imageblit(), new: 15724 cycles
cfb_imageblit(): old: 30566 cycles

In the optimized case, cfb_imageblit() is now ~2x faster than before.

v3:
    * fix commit description (Pekka)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

This patch causes crashes with arm mainstone, z2, and collie emulations.
Reverting it fixes the problem.

collie crash log and bisect log attached.

Does it work if you apply the fixes at

https://patchwork.freedesktop.org/series/101321/

?

Yes, it does, specifically the cfb related patch. I sent a Tested-by:.

Thanks,
Guenter