[Intel-gfx] [PATCH] drm/i915: Reject 446-480MHz HDMI clock on GLK

[Kahola, Mika]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Wednesday, February 3, 2021 11:31 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: stable at vger.kernel.org
> Subject: [Intel-gfx] [PATCH] drm/i915: Reject 446-480MHz HDMI clock on GLK
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The BXT/GLK DPLL can't generate certain frequencies. We already reject the
> 233-240MHz range on both. But on GLK the DPLL max frequency was
> bumped from 300MHz to 594MHz, so now we get to also worry about the
> 446-480MHz range (double the original problem range). Reject any frequency
> within the higher problematic range as well.
> 
> Cc: stable at vger.kernel.org
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3000
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Reviewed-by: Mika Kahola <mika.kahola at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_hdmi.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c
> b/drivers/gpu/drm/i915/display/intel_hdmi.c
> index 66e1ac3887c6..b593a71e6517 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> @@ -2218,7 +2218,11 @@ hdmi_port_clock_valid(struct intel_hdmi *hdmi,
>  					  has_hdmi_sink))
>  		return MODE_CLOCK_HIGH;
> 
> -	/* BXT DPLL can't generate 223-240 MHz */
> +	/* GLK DPLL can't generate 446-480 MHz */
> +	if (IS_GEMINILAKE(dev_priv) && clock > 446666 && clock < 480000)
> +		return MODE_CLOCK_RANGE;
> +
> +	/* BXT/GLK DPLL can't generate 223-240 MHz */
>  	if (IS_GEN9_LP(dev_priv) && clock > 223333 && clock < 240000)
>  		return MODE_CLOCK_RANGE;
> 
> --
> 2.26.2
> 
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