In some cases, BIOS doesn't initializes DSI panel.DSI and
backlight registers are thereby not initialized. Programming
the same in driver backlight setup.
Signed-off-by: Uma Shankar <uma.shan...@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 3 +++
drivers/gpu/drm/i915/intel_panel.c | 11 +++++++++++
2 files changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 8407b5c..10f73b1 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7166,6 +7166,9 @@ enum skl_disp_power_wells {
#define TRANS_MSA_12_BPC (3<<5)
#define TRANS_MSA_16_BPC (4<<5)
+/* Max CDCLK freq for BXT in HZ */
+#define BXT_CDCLK_MAX 624000000
+
/* LCPLL Control */
#define LCPLL_CTL 0x130040
#define LCPLL_PLL_DISABLE (1<<31)
diff --git a/drivers/gpu/drm/i915/intel_panel.c
b/drivers/gpu/drm/i915/intel_panel.c
index 9fcf86c..8225cea 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1427,6 +1427,17 @@ bxt_setup_backlight(struct intel_connector *connector,
enum pipe unused)
panel->backlight.max = I915_READ(
BXT_BLC_PWM_FREQ(panel->backlight.controller));
+ if (!panel->backlight.max) {
+ DRM_DEBUG_KMS("PWM freq not programmed by BIOS\n");
+ DRM_DEBUG_KMS("Programming PWM freq\n");
+
+ /* Max Backlight = Max CD Clock / pwm freq) */
+ panel->backlight.max = (BXT_CDCLK_MAX /
+ dev_priv->vbt.backlight.pwm_freq_hz);
+ I915_WRITE(BXT_BLC_PWM_FREQ(panel->backlight.controller),
+ panel->backlight.max);
+ }
+
val = bxt_get_backlight(connector);
panel->backlight.level = intel_panel_compute_brightness(connector, val);
--
1.7.9.5
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