How to use lvgl on pc386 BSP.

Karel Gardas karel.gardas at
Sat Sep 19 21:41:58 UTC 2020

On 9/19/20 10:32 AM, Christian Mauderer wrote:
> Hello Karel,
> I wasn't aware that there is a framebuffer driver in the PC BSP.

Yes, in fact there are three FB drivers in pc386 BSP family:

- for VGA card
- for Cirrus Logic GD5446 card
- for VESA BIOS Extension capable graphics card

The latest one is enabled by default and that's what I'm trying to use.

> Maybe
> an alternative to using the BSP framebuffer driver could be to just port
> the FreeBSD framebuffer driver for PC and use that one? That might could
> be less work than fixing the PC BSPs driver.

Hmm. Just a brief check reveals that FB also supports several FB drivers:

- for EFI frame buffer
- for KMS enabled graphics card with vt_fb backend

The former seems to be available on UEFI based systems only. The later
seems to depends on DRM code which is *huge*. I've just meassured drm
code from OpenBSD and this is more code than whole RTEMS kernel.
(git:// and that just implementing DRM for Intel
and AMD cards...

In comparison with that pc386 fbs are light weight.

Also FreeBSD vga driver which supports VESA BIOS Extensions does not
seems to enable framebuffer...

> If you want to continue to use the BSPs driver, I can try to have a more
> detailled look at it.

I think I can also do something as I do have setup here -- just try to
debug into mmap to see why it's not able to mmap /dev/fd0 and this way
get more info about the failure...

> But like I said: I would expect that the FreeBSD
> driver is simpler to use.

I'm not so sure, see above, but please correct me if I'm wrong since
especially I'm expert on neither FBSD, frame buffers and C...


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