OMAP4 has 2 LCD channels and corresponding DISPC_DIVISOR1 and DISPC_DIVISOR2 registers to configure the pixel clock frequency, for the respective LCD displays. There is also DISPC_DIVISOR register, which by default has the ENABLE bit set to zero, for backward compatibility mode. Hence the logical clock divider of DISPC_DIVISOR1.LCD, gets used for core func clk configuration. The default value of DISPC_DIVISOR1.LCD is 4. If only the secondary LCD is enabled, at high pixel resolutions the core clk lags behind the pixel clock, causing stair-step effect (diagonal lines with tearing) on the display. Hence DISPC_DIVISOR.ENABLE is set to 1, and the core functional clock is set independently and exclusively in DISPC_DIVISOR.LCD. - Added the above as dss_features ----------------------------------------------------- History ------- Changes from previous version (v1) - Fixed comments from Tomi Valkeinen <tomi.valkeinen@xxxxxx> Changes from previous version (v2) - Rebased against the DSS2 master to avoid conflicts Base ---- url = git://gitorious.org/linux-omap-dss2/linux.git branch "master" commit a2792bb44d45ef97963e67565ad1e1dd5bf0cbd7 ----------------------------------------------------- Raghuveer Murthy (3): OMAP: DSS2: Adding dss_features for independent core clk divider OMAP: DSS2: Renaming register macro DISPC_DIVISOR(ch) OMAP4: DSS2: Using dss_features to set independent core clock divider drivers/video/omap2/dss/dispc.c | 51 +++++++++++++++++++++++-------- drivers/video/omap2/dss/dss_features.c | 3 +- drivers/video/omap2/dss/dss_features.h | 2 + 3 files changed, 42 insertions(+), 14 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
