[PATCH] Add framebuffer in BBB

[Christian Mauderer]

On 28/07/2019 13:07, Vijay Kumar Banerjee wrote:
> 
> 
> 
> On Sun, Jul 28, 2019 at 1:31 PM Christian Mauderer <list at c-mauderer.de
> <mailto:list at c-mauderer.de>> wrote:
> 
>     On 27/07/2019 21:43, Vijay Kumar Banerjee wrote:
>     >
>     >
>     >
>     > On Sat, Jul 27, 2019 at 7:37 PM Christian Mauderer
>     <list at c-mauderer.de <mailto:list at c-mauderer.de>
>     > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>> wrote:
>     >
>     >     On 26/07/2019 13:41, Christian Mauderer wrote:
>     >     > On 26/07/2019 13:22, Vijay Kumar Banerjee wrote:
>     >     >> Hello everyone!
>     >     >>
>     >     >> I'm excited to post the following patchset. With this patchset
>     >     >> I have the framebuffer working in BBB and have tested it with a
>     >     >> BBB revC with HDMI connected Screen.
>     >     >>
>     >     >> This patchset uses mmap and hence it's necessary to apply the
>     >     >> patche ON TOP OF mmap patch to avoid merge conflict.
>     >     >>
>     >     >> In reply to this mail, I'll be attaching a picture of the
>     screen
>     >     >> where my rectangle drawing application made a nice red
>     rectangle
>     >     >> on the screen just like in FreeBSD.
>     >     >>
>     >     >> Thanks and regards,
>     >     >> Vijay
>     >     >>
>     >     >
>     >     > Hello Vijay,
>     >     >
>     >     > it's great that you now have a working driver. Well done.
>     >     >
>     >     > I hadn't had a look at most patches yet and most likely that
>     will
>     >     need a
>     >     > bit of time. It's a lot of stuff. Most likely the bigger
>     patches won't
>     >     > reach the mailing list so maybe adding a link to a branch on
>     your
>     >     github
>     >     > repo would be good.
>     >     >
>     >     > Note: Please don't send a v2 right now. I'm sure there are more
>     >     comments
>     >     > (maybe not only from me). Collect comments for at least one
>     or two
>     >     days
>     >     > and create an update afterwards.
>     >     >
>     >     > Some notes reading the patch overview:
>     >     >
>     >     >> [PATCH 01/10] TDA19988 : Import from FreeBSD
>     >     >> [PATCH 02/10] TDA19988 : port to RTEMS
>     >     >> [PATCH 03/10] am335x display drivers: Import from FreeBSD
>     >     >> [PATCH 04/10] am335x display drivers : Port to RTEMS
>     >     >> [PATCH 05/10] fbd : Import from FreeBSD
>     >     >> [PATCH 06/10] fbd : Port to RTEMS
>     >     >
>     >     > Is fbd a prerequisite of am335x_lcd? In that case it would
>     have been
>     >     > better to reorder the patches. As long as every version
>     compiles (to
>     >     > allow git bisect) I would accept that order too. But as a
>     general rule
>     >     > prerequisites should be prior to the parts that use it.
>     >     >
>     >     >> [PATCH 07/10] VT : Import from FreeBSD
>     >     >> [PATCH 08/10] VT : Port to RTEMS
>     >     >
>     >     > Is the vt still necessary? I think it was an intermediate
>     step to try
>     >     > whether it's initializing the display. Did you try without it?
>     >     >
>     >     >> [PATCH 09/10] TI Pinmux : Import from FreeBSD
>     >     >> [PATCH 10/10] TI Pinmux : Port to RTEMS
>     >     >
>     >     > Again: prerequisite. So they should be one of the first.
>     >     >
>     >     > Best regards
>     >     >
>     >     > Christian
>     >     >
>     >
>     >     One general question: When trying the patches, my monitor has
>     been set
>     >     up as 1440x900 instead of it's native resolution. Did you
>     check whether
>     >     the resolution on your screen is set correctly?
>     >
>     > It's not setting fb with the "preferred videomode", I can confirm that
>     > the resolution
>     > set by FreeBSD and RTEMS is same.
> 
>     OK. Sooner or later it might would be good to find out how to set
>     another resolution. Currently I have the following output:
> 
>     ````
>     Preferred mode: 1920x1200 @ 60Hz
>     Number of extension blocks: 1
>     fb0: detected videomode: 1440x900 @ 60KHz
>     fbd0 on fb0
>     ````
> 
>     It's a bit odd that not the preferred mode is used. But if it is the
>     same for FreeBSD it's OK for a start.
> 
>     One other problem: I tried to create some solid regions and it seems
>     that there are a few artefacts. Can you try that on your screen and tell
>     me whether you get them too? For the code and an image how it looks like
>     on my screen take a look at
>         https://gist.github.com/c-mauderer/051689bb1199caf20a08d9844c44c113
> 
>     Some of the lines vanished after a few seconds. I think that could be a
>     memory caching issue.
> 
> I see the same. Some lines come back after a few seconds:
> https://drive.google.com/file/d/1CA61bs0nipUygRpotmyL-Hd8khG_RIbD/view?usp=sharing 

OK. Like I said: My first guess would be a caching issue. Do you know
where or how the video memory is allocated? Is it a fixed area or
dynamically during initialization?

> 
>     >
>     >     Best regards
>     >
>     >     Christian
>     >
>