[Intel-gfx] [PATCH 8/9] drm/i915/mtl: Add C10 phy programming for HDMI

[Sripada, Radhakrishna]

> -----Original Message-----
> From: Deak, Imre <imre.deak at intel.com>
> Sent: Thursday, April 13, 2023 9:37 AM
> To: Sripada, Radhakrishna <radhakrishna.sripada at intel.com>
> Cc: intel-gfx at lists.freedesktop.org
> Subject: Re: [PATCH 8/9] drm/i915/mtl: Add C10 phy programming for HDMI
> 
> On Wed, Apr 12, 2023 at 03:49:24PM -0700, Radhakrishna Sripada wrote:
> > [...]
> > +/* Precomputed C10 HDMI PLL tables */
> > +static const struct intel_c10pll_state mtl_c10_hdmi_25175 = {
> > +	.clock = 25175,
> > +	.tx = 0x10,
> > +	.cmn = 0x1,
> > +	.pll[0] = 0x34,
> > +	.pll[1] = 0x00,
> > +	.pll[2] = 0xB0,
> > +	.pll[3] = 0x00,
> > +	.pll[4] = 0x00,
> > +	.pll[5] = 0x00,
> > +	.pll[6] = 0x00,
> > +	.pll[7] = 0x00,
> > +	.pll[8] = 0x20,
> > +	.pll[9] = 0xFF,
> > +	.pll[10] = 0xFF,
> > +	.pll[11] = 0x55,
> > +	.pll[12] = 0xE5,
> > +	.pll[13] = 0x55,
> > +	.pll[14] = 0x55,
> > +	.pll[15] = 0x0D,
> > +	.pll[16] = 0x09,
> > +	.pll[17] = 0x8F,
> > +	.pll[18] = 0x84,
> > +	.pll[19] = 0x23,
> > +};
> 
> Something off with the above table,
> intel_c10pll_calc_port_clock() calculates 25200 clock rate for it. So
> either .clock above needs to be the same rate, or the PLL params need to
> be corrected for the 25175 rate.
We do have a pre-computed table for 25200 clock which has different values.
Do we skip this clock for now?

-RK
> 
> > [...]
> > @@ -690,9 +1315,20 @@ static void intel_c10pll_update_pll(struct
> intel_crtc_state *crtc_state,
> >  static int intel_c10pll_calc_state(struct intel_crtc_state *crtc_state,
> >  				   struct intel_encoder *encoder)
> >  {
> > +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> >  	const struct intel_c10pll_state * const *tables;
> > +	enum phy phy = intel_port_to_phy(i915, encoder->port);
> >  	int i;
> >
> > +	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI)) {
> > +		if (intel_c10_phy_check_hdmi_link_rate(crtc_state->port_clock)
> > +		    != MODE_OK) {
> > +			drm_dbg_kms(&i915->drm, "Can't support HDMI link
> rate %d on phy %c.\n",
> > +				    crtc_state->port_clock, phy_name(phy));
> > +			return -EINVAL;
> > +		}
> > +	}
> 
> The above check is not needed, covered already by the loop later in
> the function.
> 
> > +
> >  	tables = intel_c10pll_tables_get(crtc_state, encoder);
> >  	if (!tables)
> >  		return -EINVAL;