On Mon, 2011-09-12 at 16:53 +0530, Archit Taneja wrote: > On Monday 12 September 2011 04:36 PM, Valkeinen, Tomi wrote: > > On Mon, 2011-09-12 at 16:31 +0530, Archit Taneja wrote: > >> On Monday 12 September 2011 02:42 PM, Valkeinen, Tomi wrote: > >>> Enabling HDMI output often causes sync lost errors, and almost always > >>> causes timeout errors being printed from dispc_mgr_enable_digit_out(). > >>> > >>> The sync lost problem seems to go lessen greatly if we first enable the > >>> HDMI output, and only then enable the DISPC output. However, as this is > >>> only based on observations, the fix may not be perfect as the problem > >>> may lie somewhere else. Nevertheless, HDMI works better with this patch. > >>> > >>> This will also fix the dispc's dispc_mgr_enable_digit_out(), as the code > >>> waits for two VSYNCs after enabling the output. If the HDMI output is > >>> disabled (as it was previously), there are no VSYNCs and > >>> dispc_mgr_enable_digit_out() will print timeout errors. > >>> > >>> Cc: Mythri P K<mythripk@xxxxxx> > >>> Signed-off-by: Tomi Valkeinen<tomi.valkeinen@xxxxxx> > >>> --- > >>> drivers/video/omap2/dss/hdmi.c | 4 ++-- > >>> 1 files changed, 2 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/drivers/video/omap2/dss/hdmi.c b/drivers/video/omap2/dss/hdmi.c > >>> index 4752137..06a78b2 100644 > >>> --- a/drivers/video/omap2/dss/hdmi.c > >>> +++ b/drivers/video/omap2/dss/hdmi.c > >>> @@ -529,10 +529,10 @@ static int hdmi_power_on(struct omap_dss_device *dssdev) > >>> dispc_set_digit_size(dssdev->panel.timings.x_res, > >>> dssdev->panel.timings.y_res); > >>> > >>> - dispc_mgr_enable(OMAP_DSS_CHANNEL_DIGIT, 1); > >>> - > >>> hdmi.ip_data.ops->video_enable(&hdmi.ip_data, 1); > >>> > >>> + dispc_mgr_enable(OMAP_DSS_CHANNEL_DIGIT, 1); > >>> + > >> > >> What content would HDMI push out till the time DIGIT is enabled? It > >> might be interesting to put some milliseconds of delay here and see what > >> happens. > > > > I guess HDMI works independently of DISPC. So HDMI will output whatever > > is in the video port from DISPC to HDMI, regardless of what DISPC does. > > My guess is it's either random bits or, more probably, zeroes. > > Okay. I thought HDMI block may probe the video port's DE line or > something to check if it is pushing out valid content. However, with > this patch, we are more aligned with what we do in power_off(), i.e > first disable the manager and then disable HDMI. Yep. But as I said in the desc, this is just based on my observations. If this is the wrong way to enable tv-output, we should check whether venc is also working the wrong way. Tomi -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
