On Thu, Jun 20, 2013 at 09:46:03PM +0200, Sebastian Hesselbarth wrote: > + ref_pix = 3 + mode->hsync_start - mode->hdisplay; > + de_pix_s = mode->htotal - mode->hdisplay; > + de_pix_e = de_pix_s + mode->hdisplay; > + hs_pix_s = mode->hsync_start - mode->hdisplay; > + hs_pix_e = hs_pix_s + mode->hsync_end - mode->hsync_start; Correct, however, these can be simplified. For de_pix_e: de_pix_e = de_pix_s + mode->hdisplay; de_pix_s = mode->htotal - mode->hdisplay; Putting de_pix_s into de_pix_e's equation, you get: de_pix_e = mode->htotal - mode->hdisplay + mode->hdisplay; which ends up simply as: de_pix_e = mode->htotal; Now, doing the same for hs_pix_e: hs_pix_e = mode->hsync_start - mode->hdisplay + mode->hsync_end - mode->hsync_start; which ends up as: hs_pix_e = mode->hsync_end - mode->hdisplay; So overall these come out as: de_pix_e = mode->htotal; de_pix_s = mode->htotal - mode->hdisplay; hs_pix_e = mode->hsync_end - mode->hdisplay; hs_pix_s = mode->hsync_start - mode->hdisplay; I've listed them in reverse order because it makes more sense to me when thinking about it. What we're basically doing is rotating this by hdisplay pixel clocks to the left, so using abbreviations: ht=htotal hds=hdisplay start hde=hdisplay end hss=hsync_start hse=hsync_end 0 ht hds hde hss hse | |-----------------------------------|----|---|----| becomes: 0 ht 0 hss hse hds hde |----|---|----|-----------------------------------| and from that you can visualize taking hdisplay (being hde-hds) off each timing parameter modulo htotal gives you the above equations. These calculations are the same as what was originally in the driver: + de_start = mode->htotal - mode->hdisplay; + de_end = mode->htotal; + hs_start = mode->hsync_start - mode->hdisplay; + hs_end = mode->hsync_end - mode->hdisplay; when it was first committed. This is otherwise exactly what I came up with which gets my TV working again in HDMI mode. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
