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

Hi

Am 01.11.21 um 09:54 schrieb Sven Schnelle:

Hi Thomas,

Thomas Zimmermann [off-list ref] writes:

quoted

Am 31.10.21 um 20:53 schrieb Sven Schnelle:

quoted

Hi List(s),
i wrote a fbdev driver for the HP Visualize FX cards used some of
the
PA-RISC workstations. It utilizes some of the 2D acceleration features
present in the card.
[..]

Thanks for all the work you put into this. We welcome drivers even for
older hardware, but not for fbdev. DRM is all the rage now and has
been for a while. I'd like to ask you to convert the driver to DRM and
resubmit to [off-list ref].

I while ago, I made conversion helpers for this. You can look at [1]
for a trivial DRM drivers that wraps existing fbdev drivers for use
with DRM. Once you have that, it turns into a refactoring job.

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]

If you need help, there's [off-list ref].

Best regards
Thomas

[1] 
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/tiny/cirrus.c

Sven

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev