Hi
Am 30.10.24 um 10:30 schrieb Helge Deller:
quoted
quoted
I'm happy to get rid of the fbdev drivers, but for that DRM really needs
to allow some sort of native fillrect, copyarea and imageblt operations so
that we can get performance back on the old cards when implementing them
as DRM driver.
This is unrelated to udl.
No, it's not.
The udl fbdev driver implements those functions (like the other fbdev drivers)
and as such fbcon on top of udl is accelerated, while fbcon on drm drivers
is unaccelerated.
Udlfb uses the regular software implementations to draw into its shadow buffer. It then schedules an update to copy the update over USB to the adapter's internal framebuffer memory. [1] Udl uses exactly the same code pattern and most of the involved helpers. [2]
[1] https://elixir.bootlin.com/linux/v6.11.5/source/drivers/video/fbdev/udlfb.c#L1145
[2] https://elixir.bootlin.com/linux/v6.11.5/source/drivers/gpu/drm/drm_fbdev_shmem.c#L39
Best regards
Thomas
Helge
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Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
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