Hi everyone,
I made some progress in the development of drm-openchrome, so I will like to
discuss the progress I have made.
I just committed a fix that will allow the FP (Flat Panel) to work solo.
Previously, FP will work only when analog VGA is used simultaneously.
In fact, I am writing this message from a computer running drm-openchrome
OpenChrome DRM and OpenChrome DDX on Xubuntu 14.04.
Like OpenChrome DDX, I am primarily developing drm-openchrome on my VIA
Technologies silicon (microprocessor + chipset) laptop. (Epic Learning 1314
laptop)
This laptop has a relatively tiny 40 GB SATA hard drive (a good condition hard
driver salvaged from a e-waste site), and with drm-openchrome consuming about
10 GB when I compile the Linux kernel 3.19-rc6 along with 4 images of
Ubuntu-based OSes for testing purposes, the hard drive is close to full at this
point.
Anyway, I have personally fixed two major bugs of drm-openchrome, but the
code itself still contains number of substantial problems.
The biggest bug drm-openchrome still contains is the fact that when the screen
resolution is changed, drm-openchrome will crash.
Since I fixed this kind of a bug with OpenChrome DDX Version 0.5 for the UMS
(User Mode Setting) side of the code, I am not too surprised that
drm-openchrome contains this bug on the KMS (Kernel Mode Setting) side of the
code.
Personally, I am trying to avoid criticizing the previous developer who worked
on drm-openchrome, but I see this as a recurring pattern that significantly
slows down the further development of the code.
I just wished previous people tested basic rudimentary features like changing
screen resolutions since this happens all the time, and this bug also made it
harder to fix the FP solo display issue since I could not attach a second
monitor (analog VGA in this case) after the computer has booted to diagnose
what is going wrong since turning on the second monitor will also cause a crash
of X.Org server.
For those who are wondering about the pace of the development, I inherited the
project without obtaining too much help or tips in how to develop the code, and
I am still trying to figure out the weird "quirks" of drm-openchrome like what
I saw with the FP solo situation.
Like in a corporate environment, if the previous developers suddenly quit, the
new people inheriting the project without the proper handover from the previous
developers will likely struggle to figure out how to fix the existing problems
even if their skill levels were high.
That is basically what I am going through right now.
I am sure the previous developer could have fixed the runtime screen resolution
change crash far faster than I would have been able to.
Regarding the major stability issues drm-openchrome still contains, these
are the known issues I am aware of.
- Runtime screen resolution change will crash X.Org server
- The display will go blank when resuming from standby
Besides those major issues, 2D acceleration is still not working although I am
fortunate to have a laptop (Epic Learning 1314 laptop with VN896 chipset) where
the rendering performance is reasonably good, so drm-openchrome is definitely
usable for development and general use purposes.
Other than those issues, the following major features are missing from
drm-openchrome
- Use of strapping resistors to aid display initialization
- Support for VIA Technologies VT1632(A) external TMDS transmitter for DVI
support
- External TV encoder support
- DisplayPort support (VX900 chipset only)
My medium term goal is to have "mostly" common display initialization code
between OpenChrome DDX UMS code and drm-openchrome OpenChrome DRM.
I quote the word "mostly" because the code cannot simply be copied between the
two, but the hardware register access procedure will become similar so that the
two will have similar behavior.
There are some aspects of drm-openchrome OpenChrome DRM that is better than the
existing OpenChrome DDX code like frame buffer size detection method, and good
aspects of drm-openchrome OpenChrome DRM will be backported to OpenChrome DDX
in the future.
I will definitely need whoever that maintains Linux DRM to give me guidance
in how to get OpenChrome DRM mainlined, but my attempt back in August 2016 got
virtually ignored.
If someone can get their attention so that they can contact me to resolve
mainlining issues, then that will be very helpful to this project, but in case
I get ignored again, I will continue the development of OpenChrome DRM with the
existing Linux kernel 3.19-rc6.
Regards,
Kevin Brace
The OpenChrome Project Maintainer / Developer
_______________________________________________
Openchrome-devel mailing list
Openchrome-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/openchrome-devel
