OMAP: DSS2: DSS: Fix context save/restore

The current method of saving and restoring the context could cause a
restore before saving, effectively "restoring" zero values to registers.

Add ctx_valid field to indicate if the saved context is valid and can be
restored.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

diff --git a/drivers/video/omap2/dss/dss.c b/drivers/video/omap2/dss/dss.c
index 2424064..9423a2e 100644 (file)
--- a/drivers/video/omap2/dss/dss.c
+++ b/drivers/video/omap2/dss/dss.c
@@ -74,6 +74,7 @@ static struct {
        enum omap_dss_clk_source dispc_clk_source;
        enum omap_dss_clk_source lcd_clk_source[MAX_DSS_LCD_MANAGERS];
 
+       bool            ctx_valid;
        u32             ctx[DSS_SZ_REGS / sizeof(u32)];
 } dss;
 
@@ -109,12 +110,19 @@ static void dss_save_context(void)
                SR(SDI_CONTROL);
                SR(PLL_CONTROL);
        }
+
+       dss.ctx_valid = true;
+
+       DSSDBG("context saved\n");
 }
 
 static void dss_restore_context(void)
 {
        DSSDBG("dss_restore_context\n");
 
+       if (!dss.ctx_valid)
+               return;
+
        RR(CONTROL);
 
        if (dss_feat_get_supported_displays(OMAP_DSS_CHANNEL_LCD) &
@@ -122,6 +130,8 @@ static void dss_restore_context(void)
                RR(SDI_CONTROL);
                RR(PLL_CONTROL);
        }
+
+       DSSDBG("context restored\n");
 }
 
 #undef SR