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drm/i915/display: Add missing checks for cdclk crawling

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cdclk_sanitize() function was written assuming vco was a signed integer.
vco gets assigned to -1 (essentially ~0) for the case where PLL
might be enabled and vco is not a frequency that will ever
get used. In such a scenario the right thing to do is disable the
PLL and re-enable it again with a valid frequency.
However the vco is declared as a unsigned variable.
With the above assumption, driver takes crawl path when not needed.
Add explicit check to not crawl in the case of an invalid PLL.

v2: Move the check from .h to .c (MattR)
- Move check to bxt_set_cdclk() instead of
intel_modeset_calc_cdclk() which is directly in
the path of the sanitize() function (Ville)

v3: remove unwanted parenthesis(Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221117230002.792096-1-anusha.srivatsa@intel.com
This commit is contained in:
Anusha Srivatsa 2022-11-17 15:00:00 -08:00
parent f322ed0d76
commit 9a0a4ec530
1 changed files with 12 additions and 1 deletions
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13
drivers/gpu/drm/i915/display/intel_cdclk.c
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@ -1717,6 +1717,16 @@ static void dg2_cdclk_squash_program(struct drm_i915_private *i915,
intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl);
}
static bool cdclk_pll_is_unknown(unsigned int vco)
{
/*
* Ensure driver does not take the crawl path for the
* case when the vco is set to ~0 in the
* sanitize path.
*/
return vco == ~0;
}
static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
const struct intel_cdclk_config *cdclk_config,
enum pipe pipe)
@ -1749,7 +1759,8 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
return;
}
if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0) {
if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0 &&
!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco)) {
if (dev_priv->display.cdclk.hw.vco != vco)
adlp_cdclk_pll_crawl(dev_priv, vco);
} else if (DISPLAY_VER(dev_priv) >= 11)