Difficulty of developing Open Source Linux drivers for GPU

During the last few days there as been an active discussion ongoing at dri-devel list about Open Source Graphics drivers. The discussion was initiated by Qualcomm's RFC message - [RFC] Qualcomm 2D/3D graphics driver.

Qualcomm's Linux team has been working on Open Sourced Kernel drivers for their chipset. What they have done so far is that they have build DRM driver with a limited set of supported functionality to enable DRI2. Their own userland parts of the drivers do still utilize the KGSL (Kernel Graphics Support Layer) interface to allocate memory making DRM just as an API to be more closer with the mainstream Linux Graphics stack. Qualcomm does still have some plans in the future to move to an standard design - possibly TTM.


The dri-devel list the opinions about drivers with an userland binary blobs was made quite clear - if you aren't going to open the whole drivers don't try to push them to mainline. Basically the door was slammed from the Qualcomm efforts for pushing the drivers in.

In between the lines I think there were some excellent point made in this discussion.
The bottom line is that the community cannot work with the drivers if there exists and dependency to closed sourced userland - this is definitely clear. With this kind of an setup it is just impossible to work with the drivers. On the otherhand if the community is going to bombard down all the drivers with the closed userland parts (even without making sure what are the attemts to open source them) how are we ever going to see open sourced mobile GPU drivers? From my point of view the community also has the means to guide this work to right direction - giving comments to the request. It really seems that the Qualcomm guys do have the enthusiasm to develop the open source drivers. How about making sure that these guys are taking the correct steps also with the userland and making sure that the Kernel bits are as they should?

GLES1.1/2.0 on Mesa DRI and a bit about Gallium

Mesa has had GLES 1.1/2.0 already since since last year through Gallium state trackers. What this means is that Gallium based drivers are capable of providing support GLES support for end users. Now there is also an activity ongoing to get the Mesa GLES1/2 support to work with DRI drivers and along that to expose multiple GL APIs without separate state trackers on Gallium side.

This work on GLES 1.1/2.0 on DRI made by Kristian received good feedback also Gallium driver developer and is now merged to Mesa.


The discussion about classic Mesa vs. Mesa Gallium State Tracker in general has not lately been this productive (see the Mesa thread). Intel guys are clearly wanting to stay with the classic drivers, and whom could actually blame after all the work that Intel has place to get their drivers to perform. Currently Nouveau camp is the only one that is really utilising Gallium3D and the RedHat guys are going to ship the latest free software NVIDIA bits with the upcoming Fedora 13.

DRI2 driver for Mesa EGL

Couple of weeks ago there was an announcement that Wayland would be moving to Mesa EGL and drop its dependencies to its own Wayland specific Eagle EGL stack. The Eagle is a non-conformant EGL loader for the DRI drivers originally develped by Kristian Høgsberg as an "side product" of his DRI2 work. Eagle as an lightweight and with its way of integrating EGL directly to KMS/DRM, was the solution for Wayland - this at least until recently.

Major reason to allow Wayland to jump to Mesa EGL is Kristian's work for the work behind the DRI2 driver for EGL and to get the Eagle EGL parts as officially to Mesa. This work - EGL on DRI2 is firstly aiming to implement this support through X, but the longer term goal seems to be that the implementation would be standalone - working directly with KMS/DRM and making it suitable for Wayland purposes.

Current plan is that the DRI2 parts for the Mesa EGL would be integrated to the upcoming Mesa 7.8 - planned to be release during this month. This is good news especially for Wayland. Along the Mesa integration the Wayland enablers are now even more mainlined. This move will most definitely make Wayland it self more attractive to outside world.