[Intel-gfx] Backlight testing

[Lukas Hejtmanek]

Hello Jesse,

unfortunately, the latest head of the intel driver has problem with backlight
setting again.

If I change backlight setting while the xserver is running (using /sys
interface), using mplayer resets the setting back to the previous value.

I think it happens if I set backlight level and then call DPMS from On to On.
The current code does not reread the current value. The following patch works
for me:

diff --git a/src/i830_lvds.c b/src/i830_lvds.c
index 1562c21..2452513 100644
--- a/src/i830_lvds.c
+++ b/src/i830_lvds.c
@@ -69,6 +69,7 @@ struct i830_lvds_priv {
     void (*set_backlight)(xf86OutputPtr output, int level);
     int (*get_backlight)(xf86OutputPtr output);
     int backlight_max;
+    char dpms;
     enum pfit_mode fitting_mode;
     uint32_t pfit_control;
     uint32_t pfit_pgm_ratios;
@@ -395,16 +396,20 @@ i830SetLVDSPanelPower(xf86OutputPtr output, Bool on)
         * controller for example), so on them, when turning LVDS back on,
         * they'll always re-maximize the brightness.
         */
-       if (!(INREG(PP_CONTROL) & POWER_TARGET_ON) &&
+       if (!(INREG(PP_CONTROL) & POWER_TARGET_ON) && 
            dev_priv->backlight_duty_cycle == 0)
            dev_priv->backlight_duty_cycle = dev_priv->backlight_max;
 
+       if (!dev_priv->dpms)
+           dev_priv->backlight_duty_cycle = dev_priv->get_backlight(output);
+
        OUTREG(PP_CONTROL, INREG(PP_CONTROL) | POWER_TARGET_ON);
        do {
            pp_status = INREG(PP_STATUS);
        } while ((pp_status & PP_ON) == 0);
 
        dev_priv->set_backlight(output, dev_priv->backlight_duty_cycle);
+       dev_priv->dpms = 0;
     } else {
        /*
         * Only save the current backlight value if we're going from
@@ -413,6 +418,7 @@ i830SetLVDSPanelPower(xf86OutputPtr output, Bool on)
        if (INREG(PP_CONTROL) & POWER_TARGET_ON)
            dev_priv->backlight_duty_cycle = dev_priv->get_backlight(output);
        dev_priv->set_backlight(output, 0);
+       dev_priv->dpms = 1;
 
        OUTREG(PP_CONTROL, INREG(PP_CONTROL) & ~POWER_TARGET_ON);
        do {
@@ -1222,6 +1228,7 @@ i830_lvds_init(ScrnInfoPtr pScrn)
 
     dev_priv = (struct i830_lvds_priv *) (intel_output + 1);
     intel_output->dev_priv = dev_priv;
+    dev_priv->dpms = 0;
 
     /* Set up the LVDS DDC channel.  Most panels won't support it, but it can
      * be useful if available.

-- 
Lukáš Hejtmánek