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Commit 26eeea15 authored by Aditya Swarup's avatar Aditya Swarup Committed by Maarten Lankhorst
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drm/i915/icl: Fix CRC mismatch error for DP link layer compliance 



Setting the pixel rounding bit to 1 in PIPE_CHICKEN register allows
to passthrough FB pixels unmodified across pipe. This fixes the failures
for DP link layer compliance tests 4.4.1.1, 4.4.1.2 & 4.4.1.3.
(Lineage #1605353570)

v2: This is also needed to fix failing IGT test case kms_cursor_crc on
ICL.(Mika Kahola)
Make macros consistent with i915_reg.h comments.(Jani Nikula)

Cc: Clint Taylor <clinton.a.taylor@intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: default avatarAditya Swarup <aditya.swarup@intel.com>
Reviewed-by: default avatarMika Kahola <mika.kahola@intel.com>
Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190307021412.18626-1-aditya.swarup@intel.com
References: https://bugs.freedesktop.org/show_bug.cgi?id=103232
parent f4ecb8ae

drivers/gpu/drm/i915/i915_reg.h

+7 −6
Original line number Diff line number Diff line
@@ -7662,9 +7662,10 @@ enum { 
#define _PIPEA_CHICKEN				0x70038

#define _PIPEB_CHICKEN				0x71038

#define _PIPEC_CHICKEN				0x72038

#define  PER_PIXEL_ALPHA_BYPASS_EN	(1 << 7)

#define PIPE_CHICKEN(pipe)			_MMIO_PIPE(pipe, _PIPEA_CHICKEN,\

							   _PIPEB_CHICKEN)

#define   PIXEL_ROUNDING_TRUNC_FB_PASSTHRU 	(1 << 15)

#define   PER_PIXEL_ALPHA_BYPASS_EN		(1 << 7)



/* PCH */

drivers/gpu/drm/i915/intel_display.c

+7 −1
Original line number Diff line number Diff line
@@ -3933,7 +3933,13 @@ static void icl_set_pipe_chicken(struct intel_crtc *crtc) 
	 * and rounding for per-pixel values 00 and 0xff

	 */

	tmp |= PER_PIXEL_ALPHA_BYPASS_EN;



	/*

	 * Display WA # 1605353570: icl

	 * Set the pixel rounding bit to 1 for allowing

	 * passthrough of Frame buffer pixels unmodified

	 * across pipe

	 */

	tmp |= PIXEL_ROUNDING_TRUNC_FB_PASSTHRU;

	I915_WRITE(PIPE_CHICKEN(pipe), tmp);

}