Commit 297c76d9 authored by Imre Deak's avatar Imre Deak
Browse files

drm/i915/dp: Reuse intel_dp_{max,effective}_data_rate in intel_link_compute_m_n() 



Reuse intel_dp_max_data_rate() and intel_dp_effective_data_rate() in
intel_link_compute_m_n(), instead of open-coding the equivalent. Note
the kbit/sec -> kByte/sec unit change in the M/N values, but this not
reducing the precision, as the link rate value is based anyway on a less
precise 10 kbit/sec value.

Suggested-by: default avatarJani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231116131841.1588781-12-imre.deak@intel.com
parent b9de01d8

drivers/gpu/drm/i915/display/intel_display.c

+3 −22
Original line number Diff line number Diff line
@@ -2388,36 +2388,17 @@ static void compute_m_n(u32 *ret_m, u32 *ret_n, 
	intel_reduce_m_n_ratio(ret_m, ret_n);

}



static void

add_bw_alloc_overhead(int link_clock, int bw_overhead,

		      int pixel_data_rate, int link_data_rate,

		      u32 *data_m, u32 *data_n)

{

	bool is_uhbr = drm_dp_is_uhbr_rate(link_clock);

	int ch_coding_efficiency =

		drm_dp_bw_channel_coding_efficiency(is_uhbr);



	*data_m = DIV_ROUND_UP_ULL(mul_u32_u32(pixel_data_rate, bw_overhead),

				   1000000);

	*data_n = DIV_ROUND_DOWN_ULL(mul_u32_u32(link_data_rate, ch_coding_efficiency),

				     1000000);

}



void

intel_link_compute_m_n(u16 bits_per_pixel_x16, int nlanes,

		       int pixel_clock, int link_clock,

		       int bw_overhead,

		       struct intel_link_m_n *m_n)

{

	u32 data_clock = DIV_ROUND_UP(bits_per_pixel_x16 * pixel_clock, 16);

	u32 link_symbol_clock = intel_dp_link_symbol_clock(link_clock);

	u32 data_m;

	u32 data_n;

	u32 data_m = intel_dp_effective_data_rate(pixel_clock, bits_per_pixel_x16,

						  bw_overhead);

	u32 data_n = intel_dp_max_data_rate(link_clock, nlanes);



	add_bw_alloc_overhead(link_clock, bw_overhead,

			      data_clock,

			      link_clock * 10 * nlanes,

			      &data_m, &data_n);

	/*

	 * Windows/BIOS uses fixed M/N values always. Follow suit.

	 *