Commit 09f21bee authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/i915: Deobfuscate wm linetime calculation 



intel_get_linetime_us() is a mess. Rewrite it in a straightforward
manner. Also the checks for the !active and pixel_rate==0 are
completely pointless here since we know that the plane is visible.

Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250919180838.10498-3-ville.syrjala@linux.intel.com


Reviewed-by: default avatarVinod Govindapillai <vinod.govindapillai@intel.com>
parent ea1a866a

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

+4 −17
Original line number Diff line number Diff line
@@ -1636,24 +1636,12 @@ skl_wm_method2(u32 pixel_rate, u32 pipe_htotal, u32 latency, 
	return ret;

}



static uint_fixed_16_16_t

static int

intel_get_linetime_us(const struct intel_crtc_state *crtc_state,

		      int pixel_rate)

{

	struct intel_display *display = to_intel_display(crtc_state);

	u32 crtc_htotal;

	uint_fixed_16_16_t linetime_us;



	if (!crtc_state->hw.active)

		return u32_to_fixed16(0);



	if (drm_WARN_ON(display->drm, pixel_rate == 0))

		return u32_to_fixed16(0);



	crtc_htotal = crtc_state->hw.pipe_mode.crtc_htotal;

	linetime_us = div_fixed16(crtc_htotal * 1000, pixel_rate);



	return linetime_us;

	return DIV_ROUND_UP(crtc_state->hw.pipe_mode.crtc_htotal * 1000,

			    pixel_rate);

}



static int
@@ -1741,8 +1729,7 @@ skl_compute_wm_params(const struct intel_crtc_state *crtc_state, 
	wp->y_tile_minimum = mul_u32_fixed16(wp->y_min_scanlines,

					     wp->plane_blocks_per_line);



	wp->linetime_us = fixed16_to_u32_round_up(intel_get_linetime_us(crtc_state,

									plane_pixel_rate));

	wp->linetime_us = intel_get_linetime_us(crtc_state, plane_pixel_rate);



	return 0;

}