Re: [PATCH/RFT] fbdev driver for HP Visualize FX cards

Thomas Zimmermann [off-list ref] writes:

Hi

Am 01.11.21 um 09:54 schrieb Sven Schnelle:

quoted

Hi Thomas,
Thomas Zimmermann [off-list ref] writes:
Thanks, i wasn't aware as i normally don't do any graphics related
development. I take a look at dri and port the driver, which is
hopefully not too hard.

Sounds good.

The one big difference when converting is that DRM really wants
drivers to support 32-bit XRGB colors. It's not a DRM limitation per
se, but a requirement of today's userspace programs. AFAICS your fbdev
driver uses a 256-color palette format. So the DRM driver would have
to convert
XRGB8888 to 8-bit RGB332 and install a corresponding palette. Don't
worry, it's easy. Take a look at the cirrus driver for a simple DRM
driver. [1]

I have converted the driver, but am using FORMAT_C8 because i haven't
figured out yet how to switch the card to XRGB8888. That's still on the
TODO list.

One question about hw blitting: with the old fbdev framework one could
replace the fb_imageblit function. For normal console text, this
function gets called with a monochrome bitmap, and an fg/bg color value.
This makes it easy to use HW accelerated blitting for text. In the
gpu/drm drivers i think i found only one driver (nouveau) doing this and
that was via the drm fbdev layer.

Is that still the way to go, or is there a better way to do HW accelerated
text blitting?

Thanks
Sven