[PATCH] Add framebuffer in BBB

Vijay Kumar Banerjee vijaykumar9597 at gmail.com
Mon Jul 29 08:40:58 UTC 2019


On Sun, Jul 28, 2019 at 5:11 PM Christian Mauderer <list at c-mauderer.de>
wrote:

> 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?
>
> Hi,

Firstly, I have reordered the patches and removed unnecessary stuff from the
patches. I have also checked that each commit builds individually. The
commits
are pushed in the following branch, please have a look:
https://github.com/thelunatic/rtems-libbsd/tree/fb-update

About video memory: I'm not sure. Maybe following the fbd_register from
fbd.c
in a debugger will give some clue. I will have a look and report.



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