On Wed, Nov 23, 2016 at 03:37:24PM +0200, Jani Nikula wrote: > On Tue, 22 Nov 2016, Manasi Navare <manasi.d.navare@xxxxxxxxx> wrote: > > The intel_dp_autotest_video_pattern() function gets invoked through the > > compliance test handler on a HPD short pulse if the test type is > > set to DP_TEST_VIDEO_PATTERN. This performs the DPCD registers > > reads to read the requested test pattern, video pattern resolution, > > frame rate and bits per color value. The results of this analysis > > are handed off to userspace so that the userspace app can set the > > video pattern mode appropriately for the test result/response. > > > > The compliance_test_active flag is set at the end of the individual > > test handling functions. This is so that the kernel-side operations > > can be completed without the risk of interruption from the userspace > > app that is polling on that flag. > > I've brought this up before, but I think for this stuff the way to go is > to have the userspace read the DPCD directly. We have the dev node for > it. > > With the approach in this patch, we'll just end up reading a bunch of > stuff from DPCD in kernel, doing error handling for that, decoding and > sanity checking the values, putting them in debugfs for the userspace to > read, having userspace code read debugfs, doing error handling for that, > decoding and sanity checking the data, finally doing something based on > the data. > > You'll also get a *much* faster turnaround for getting your userspace > code done than getting all of this in kernel first, then tweaking your > userspace, having to update both of those in lockstep, etc. When this is > based on reading DPCD directly, you can just add new stuff quickly in > userspace, with no kernel dependency. > > The easiest way would be to have an indication in debugfs for userspace > that there's something interesting in DPCD. Just a simple thing. Or just have the kernel fire off an uevent... -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
