DRMFS Pseudo File-System Proposed

Intel developers are proposing the introduction of a new pseudo file-system intended as a better fit for Direct Rendering Manager drivers rather than the mix of sysfs/debugfs usage currently used.

Swati Dhingra of Intel laid out the case this morning for the introduction of "DRMFS" with this explanation:

Currently, for the purpose of providing output debug/loggging/crc and various other kinds of data from DRM layer to userspace, we don't have a standard filesystem, which would suffice for all the usecases. The filesystems used currently such as debugfs/sysfs have their own constraints and are intended to output a particular type of data. For instance, sysfs is suitable for exporting only small data in form of attributes, thus not suitable to export large data such as error states/logs/crc etc. Likewise for debugfs, which is not available in production kernels, and may not be best place to hold certain kinds of data. As a result, we currently are creating certain files in these filesystems, which are not particularly suited there (For, i915, guc_log is a case in point, which is currently created in debugfs, but not particularly suited there).

Due to these constraints, there is a need for a new pseudo filesytem, customizable to DRM specific requirements and catering to the needs to DRM subsystem components. This will provide a unified location to hold various kinds of data from Linux DRM subsystems, for the files which can't really fit anywhere else into the existing filesystems.

Swati is currently floating it as an RFC patch series to see what other DRM driver developers think of this DRMFS concept and if they see the need to adopt it too.