On Wed, 23 Nov 2016, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > 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... I know, I know, I had that written in my mail already, but swallowed it not to add another dependency on another new UABI... we can do that later. BR, Jani. -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
