Hi, could I get some feedback on this patch, please?
Simon
On Fri, Oct 14, 2011 at 4:46 PM, Simon Que <s...@chromium.org> wrote:
> In the native backlight driver, use 4096 (0x1000) as the default backlight
> period, and use the period as the default max brightness.
>
> The default brightness is defined in a separate function that can be
> expanded to allow for different defaults on different systems in the
> future.
>
> Change-Id: Ie783b53dd034dcd7bf42e24ffc911cf2f10a5676
> Signed-off-by: Simon Que <s...@chromium.org>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 1 +
> drivers/gpu/drm/i915/intel_panel.c | 22 ++++++++++++++++++----
> 2 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h
> index 5d5def7..a832028 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3275,6 +3275,7 @@
> #define PWM_POLARITY_ACTIVE_HIGH2 (0 << 28)
>
> #define BLC_PWM_PCH_CTL2 0xc8254
> +#define BLC_PWM_PCH_FREQ_SHIFT 16
>
> #define PCH_PP_STATUS 0xc7200
> #define PCH_PP_CONTROL 0xc7204
> diff --git a/drivers/gpu/drm/i915/intel_panel.c
> b/drivers/gpu/drm/i915/intel_panel.c
> index 05f500c..8205945 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -161,6 +161,12 @@ static u32 i915_read_blc_pwm_ctl(struct
> drm_i915_private *dev_priv)
> return val;
> }
>
> +static u32 intel_panel_get_default_backlight_period(struct drm_device
> *dev)
> +{
> + /* The default number of clock cycles in one backlight PWM period.
> */
> + return 0x1000;
> +}
> +
> u32 intel_panel_get_max_backlight(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -168,11 +174,19 @@ u32 intel_panel_get_max_backlight(struct drm_device
> *dev)
>
> max = i915_read_blc_pwm_ctl(dev_priv);
> if (max == 0) {
> - /* XXX add code here to query mode clock or hardware clock
> - * and program max PWM appropriately.
> + /* If no max backlight was found, use the default PWM
> period as
> + * the max backlight value.
> */
> - printk_once(KERN_WARNING "fixme: max PWM is zero.\n");
> - return 1;
> + max = intel_panel_get_default_backlight_period(dev);
> + if (HAS_PCH_SPLIT(dev_priv->dev)) {
> + u32 val = max << BLC_PWM_PCH_FREQ_SHIFT;
> + I915_WRITE(BLC_PWM_PCH_CTL2, val);
> + } else {
> + u32 val = max << BACKLIGHT_MODULATION_FREQ_SHIFT;
> + I915_WRITE(BLC_PWM_CTL, val);
> + }
> +
> + return max;
> }
>
> if (HAS_PCH_SPLIT(dev)) {
> --
> 1.7.2.3
>
>
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