Monday, 5 July 2010

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?

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