On Thu, Nov 16, 2023 at 03:18:41PM +0200, Imre Deak wrote:
> 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: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_display.c | 25 +++-----------------
> 1 file changed, 3 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 744c321792fcf..199ecd8879461 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2389,36 +2389,17 @@ 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.
> *
> --
> 2.39.2
--
Ville Syrjälä
Intel
