On Mon, 2012-07-30 at 19:11 -0500, Ricardo Neri wrote: > DSS code wrongly assumes that VENC is always available as source for the external > sync signal for the display controller DIGIT channel. One cannot blindly > rely only on the value of DSS_CONTROL[15] as on certain processors (e.g., OMAP5) > reading/writing on that bit may not be valid. If the the sync source is not read > correctly, the callers of dss_get_hdmi_venc_clk_source might make wrong assumptions > about, for instance, video timings. > > This patch adds logic to correctly get the sync signal based on the > available displays in the DIGIT channel. A kernel BUG is thrown if an > invalid source is selected. > > Signed-off-by: Ricardo Neri <ricardo.neri@xxxxxx> > --- > v2: use BUG_ON() to simplify handling of invalid cases. > drivers/video/omap2/dss/dss.c | 13 +++++++++++-- > 1 files changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/omap2/dss/dss.c b/drivers/video/omap2/dss/dss.c > index 04b4586..2f8e4b6 100644 > --- a/drivers/video/omap2/dss/dss.c > +++ b/drivers/video/omap2/dss/dss.c > @@ -648,9 +648,15 @@ void dss_set_dac_pwrdn_bgz(bool enable) > REG_FLD_MOD(DSS_CONTROL, enable, 5, 5); /* DAC Power-Down Control */ > } > > -void dss_select_hdmi_venc_clk_source(enum dss_hdmi_venc_clk_source_select hdmi) > +void dss_select_hdmi_venc_clk_source(enum dss_hdmi_venc_clk_source_select src) > { > - REG_FLD_MOD(DSS_CONTROL, hdmi, 15, 15); /* VENC_HDMI_SWITCH */ > + enum omap_display_type dp; > + dp = dss_feat_get_supported_displays(OMAP_DSS_CHANNEL_DIGIT); > + > + BUG_ON((src == DSS_VENC_TV_CLK) && !(dp & OMAP_DISPLAY_TYPE_VENC)); > + BUG_ON((src == DSS_HDMI_M_PCLK) && !(dp & OMAP_DISPLAY_TYPE_HDMI)); > + > + REG_FLD_MOD(DSS_CONTROL, src, 15, 15); /* VENC_HDMI_SWITCH */ > } This one will still write to the reserved bit 15 on OMAP5. Perhaps we could check if both VENC and HDMI are supported, and if not, return. Tomi
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