Re: [PATCH 0/2] Add monochrome framebuffer support to simple-framebuffer

[Thomas Zimmermann]

Hi

Am 11.11.26 um 12:15 schrieb Hans de Goede:
> Hi Sebastian,
>
> On 4-Nov-26 03:34, Sebastian Raase wrote:
> > This patch series adds support for monochrome framebuffers (1 bpp, packed-pixel)
> > to simple-framebuffer.
> >
> > Monochrome framebuffers require far less video memory and bandwidth than
> > 16bpp or 32bpp framebuffers, making them useful for small devices or FPGA
> > implementations.
> Thank you for your patch-series and I see that Helge has just
> applied this to the fbdev tree.
>
> Have you considered also extending the simpledrm driver to also
> support these monochrome formats there ?
>
> Most Linux distributions now a days have switched from using simplefb
> to using simpledrm.
>
> But I must admit I've no idea how well the drm subsys / kernel-mode-
> setting API handles monochrome formats.

Only kind of. We either support it natively if the compositor can handle 
it, or we convert from XRGB8888 to the internal pixel format. But our 
helpers for converting pixel formats expect 8-bit per pixel at a 
minimum. All the drivers with lower pixel size do some kind of 
workaround. I'd love to see better support, but had no time to work on it.

Best regards
Thomas


> Regards,
>
> Hans

--
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Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
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