Hello everybody, having a monitor provide wrong or invalid EDID information – or none at all – seems to be a problem quite a number of people are facing. A few of the non-KMS X-drivers provide individual mechanisms for overriding such an EDID with user provided data. To my knowledge at least the kernel currently falls short of providing such a mechanism. This set of patches attempts to provide one. It has a number of potential shortcoming to which I was not yet able to find any solution. These are: 1. It uses drm_get_connector_name to identify a connector. I am not entirely sure though if these names are guaranteed to be unique (the names used in /sys/class/drm seem to suggest they are not). Since they are good enough for the kernel's video parameter, though, I figured they should be good enough for the present purpose as well. 2. One of the patches introduces a new kernel parameter (edid_override). This parameter takes either the raw edid-data encoded as a hex-string or the name of a firmware file from which to load the data. I am a bit unhappy with both solutions since the first puts raw data on the command line and makes it rather long and the second… well edid-data is not exactly firmware in the strict sense. It may be firm, but it is probably not ware. 3. I thought about making the sysfs code more sophisticated so that individual bytes could be written at any position within the data. Yet, there seems to be no way to truncate a file in sysfs which would be important when changing the number of 128 byte blocks the data is made up of. In addition, I cannot see what good such a behaviour would be or how the obscure use probably is somewhere out there could justify the additional complexity. I therefore opted for the approach of only allowing writes of complete edid-blobs in one pass. The patches I submit were tested on an x64 with radeon graphics and on an x86 with i915. They were made for 3.4. drivers/gpu/drm/drm_edid.c | 399 +++++++++++++++++++++++++++++++++++++++++++- drivers/gpu/drm/drm_sysfs.c | 43 ++++ include/drm/drm_crtc.h | 2 3 files changed, 435 insertions(+), 9 deletions(-) _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
