1. 03 May, 2012 2 commits
    • Chandrabhanu Mahapatra's avatar
      OMAPDSS: DISPC: Handle synclost errors in OMAP3 · 7faa9233
      Chandrabhanu Mahapatra authored
      In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
      and timing related limitations leading to SYNCLOST errors. Whenever the image
      window is moved towards the right of the screen SYNCLOST errors become
      frequent. Checks have been implemented to see that DISPC driver rejects
      configuration exceeding above limitations.
      
      This code was successfully tested on OMAP3. This code is written based on code
      written by Ville Syrjälä <ville.syrjala@nokia.com> in Linux OMAP kernel. Ville
      Syrjälä <ville.syrjala@nokia.com> had added checks for video overlay horizontal
      timing and DISPC horizontal blanking length limitations.
      Signed-off-by: default avatarChandrabhanu Mahapatra <cmahapatra@ti.com>
      Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
      7faa9233
    • Chandrabhanu Mahapatra's avatar
      OMAPDSS: DISPC: Enable predecimation · aed74b55
      Chandrabhanu Mahapatra authored
      In OMAP3 and OMAP4, the DISPC Scaler can downscale an image up to 4 times, and
      up to 2 times in OMAP2. However, with predecimation, the image can be reduced
      to 16 times by fetching only the necessary pixels in memory. Then this
      predecimated image can be downscaled further by the DISPC scaler.
      
      The pipeline is configured to use a burst of size 8 * 128 bits which consists
      of 8 mini bursts of 16 bytes each. So, horizontal predecimation more than 16
      can lead to complete discarding of such mini bursts. L3 interconnect may
      handover the bus to some other initiator and inturn delay the fetching of
      pixels leading to underflows. So, maximum predecimation limit is fixed at 16.
      
      Based on the downscaling required, a prior calculation of predecimation values
      for width and height of an image is done. Since, Predecimation reduces quality
      of an image higher priorty is given to DISPC Scaler for downscaling.
      
      This code was successfully tested on OMAP2, OMAP3 and OMAP4. Horizontal and
      vertical predecimation worked fine except for some synclost errors due to
      undocumented errata in OMAP3 which are fixed later and skewed images were seen
      on OMAP2 and OMAP3 during horizontal predecimation which will be addressed in
      the future patches.
      
      This code is based on code written by Lajos Molnar <lajos@ti.com> who had added
      predecimation support for NV12/YUV/rotated/SDMA buffers.
      Signed-off-by: default avatarChandrabhanu Mahapatra <cmahapatra@ti.com>
      Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
      aed74b55
  2. 23 Apr, 2012 17 commits
  3. 21 Apr, 2012 21 commits