[Intel-gfx] [PATCH] drm/i915: Get correct display clock on 945gm
Ville Syrjälä
ville.syrjala at linux.intel.com
Fri Jan 27 16:23:36 UTC 2017
On Fri, Jan 27, 2017 at 03:44:27PM +0100, Arthur Heymans wrote:
> This is according to Mobile Intel® 945 Express Chipset
> Family datasheet.
>
> Signed-off-by: Arthur Heymans <arthur at aheymans.xyz>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 2 +-
> drivers/gpu/drm/i915/intel_display.c | 27 +++++++++++++++++++++++++--
> 2 files changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 70d96162def6..c3141e40d938 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -114,7 +114,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> #define GCFGC 0xf0 /* 915+ only */
> #define GC_LOW_FREQUENCY_ENABLE (1 << 7)
> #define GC_DISPLAY_CLOCK_190_200_MHZ (0 << 4)
> -#define GC_DISPLAY_CLOCK_333_MHZ (4 << 4)
> +#define GC_DISPLAY_CLOCK_333_320_MHZ (4 << 4)
> #define GC_DISPLAY_CLOCK_267_MHZ_PNV (0 << 4)
> #define GC_DISPLAY_CLOCK_333_MHZ_PNV (1 << 4)
> #define GC_DISPLAY_CLOCK_444_MHZ_PNV (2 << 4)
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 81c11499bcf0..307fc62e7c70 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7389,6 +7389,26 @@ static int i945_get_display_clock_speed(struct drm_device *dev)
> return 400000;
> }
>
> +static int 945gm_get_display_clock_speed(struct drm_device *dev)
> +{
> + struct pci_dev *pdev = dev->pdev;
> + u16 gcfgc = 0;
> +
> + pci_read_config_word(pdev, GCFGC, &gcfgc);
> +
> + if (gcfgc & GC_LOW_FREQUENCY_ENABLE)
> + return 133333;
> + else {
> + switch (gcfgc & GC_DISPLAY_CLOCK_MASK) {
> + case GC_DISPLAY_CLOCK_333_320_MHZ:
> + return 320000;
That indeed is what the docs say.
The code is tantalizingly close to the 915gm code now, so maybe
we could share it with a simple
if (IS_915GM(dev_priv))
return 320000;
else
return 333333;
?
Now if someone could figure out where to dig up the DDR and FSB clocks
we could also fix up the 190 vs. 200 MHz case...
> + default:
> + case GC_DISPLAY_CLOCK_190_200_MHZ:
> + return 200000;
> + }
> + }
> +}
> +
> static int i915_get_display_clock_speed(struct drm_device *dev)
> {
> return 333333;
> @@ -7435,7 +7455,7 @@ static int i915gm_get_display_clock_speed(struct drm_device *dev)
> return 133333;
> else {
> switch (gcfgc & GC_DISPLAY_CLOCK_MASK) {
> - case GC_DISPLAY_CLOCK_333_MHZ:
> + case GC_DISPLAY_CLOCK_333_320_MHZ:
> return 333333;
> default:
> case GC_DISPLAY_CLOCK_190_200_MHZ:
> @@ -15991,9 +16011,12 @@ void intel_init_display_hooks(struct drm_i915_private *dev_priv)
> else if (IS_I915G(dev_priv))
> dev_priv->display.get_display_clock_speed =
> i915_get_display_clock_speed;
> - else if (IS_I945GM(dev_priv) || IS_845G(dev_priv))
> + else if (IS_845G(dev_priv))
> dev_priv->display.get_display_clock_speed =
> i9xx_misc_get_display_clock_speed;
> + else if (IS_I945GM(dev_priv))
> + dev_priv->display.get_display_clock_speed =
> + 954gm_get_display_clock_speed;
> else if (IS_I915GM(dev_priv))
> dev_priv->display.get_display_clock_speed =
> i915gm_get_display_clock_speed;
> --
> 2.11.0
>
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--
Ville Syrjälä
Intel OTC
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