From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6634BD2F005 for ; Tue, 27 Jan 2026 12:18:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F2E9F10E553; Tue, 27 Jan 2026 12:18:32 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="g1HY5bLk"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0748210E089; Tue, 27 Jan 2026 12:18:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1769516311; x=1801052311; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=rV/4MGo52M6b/K1M4C5ns/3j8iDtPTwx6O2SN4szxak=; b=g1HY5bLkSaUz567yCwQNlYLM+/YQQNjnFOIIQrhZ574RXCAucHhjUCrf ptGD+YIuPd5YF3vDOYYhfNnkxFKoQeF+5wxAEbP9J1zASDV/kPIpgCsUx G9h/DoT5VB/LnUl6ZobNZtByhLIHz+0Ea0PjJMami4b/S7unKpXcyg35m H9wsMsxfH4ScM9ph9fd3BALlUIFnXB9o/J5kFDcoRinIdcQ/GNiuMEPBU 3Tih6vDyHlttttJqJ5ppJXx8RtWvSyOC7EPBp2UGY04Lhx9CvOm65OlTX VTdMddBrxa2FUSm6l7IJW4VrtwXnOce8F2s+UjYji7uwNnrJhqglfdStV Q==; X-CSE-ConnectionGUID: fwTpBZazR7WhYsJ/XhAYww== X-CSE-MsgGUID: SoKUcOtdT866oQkm8hM+hQ== X-IronPort-AV: E=McAfee;i="6800,10657,11683"; a="70612426" X-IronPort-AV: E=Sophos;i="6.21,257,1763452800"; d="scan'208";a="70612426" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2026 04:18:16 -0800 X-CSE-ConnectionGUID: 3VLZlJJWQmCpWFwaMk8C+Q== X-CSE-MsgGUID: /yS8puqNRYq0Jqph28SlIA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,257,1763452800"; d="scan'208";a="207583463" Received: from amilburn-desk.amilburn-desk (HELO localhost) ([10.245.244.86]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2026 04:18:14 -0800 Date: Tue, 27 Jan 2026 14:18:11 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Vinod Govindapillai Cc: intel-xe@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, uma.shankar@intel.com, juha-pekka.heikkila@intel.com Subject: Re: [PATCH v3] drm/i915/display: fix the pixel normalization handling for xe3p_lpd Message-ID: References: <20260127111345.939736-1-vinod.govindapillai@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260127111345.939736-1-vinod.govindapillai@intel.com> X-Patchwork-Hint: comment Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, Jan 27, 2026 at 01:13:45PM +0200, Vinod Govindapillai wrote: > Pixel normalizer is enabled with normalization factor as 1.0 for > FP16 formats in order to support FBC for those formats in xe3p_lpd. > Previously pixel normalizer gets disabled during the plane disable > routine. But there could be plane format settings without explicitly > calling the plane disable in-between and we could endup keeping the > pixel normalizer enabled for formats which we don't require that. > This is causing crc mismatches in yuv formats and FIFO underruns in > planar formats like NV12. > > Fix this by updating the pixel normalizer configuration based on the > pixel formats explicitly during the plane settings arm calls itself > - enable it for FP16 and disable it for other formats in HDR capable > planes. To avoid redundancies in these updates, normalization factor > between old and new plane states are compared before the update. The > function to check validity of the fp16 formats for fbc is now updated > to return the normalization factor as 1.0 in case of fp16 formats and > 0 in other cases. This looks incredibly complex for just writing a single register. I think it should be just somehting like: static u32 pixel_normalizer_val() { if (!need_pixel_normalizer()) return 0; return ENABLE | FACTOR; } plane_update(..) { ... if (HAS_PIXEL_NORMALIZER()) write(PIXEL_NOFMRALIZER, pixel_normalizer_val()) ... } plane_disable() { ... // do we even need to disable it for disabled planes? if (HAS_PIXEL_NORMALIZER()) write(PIXEL_NORMALIZER, 0); ... } > > v2: avoid redundant pixel normalization setting updates > > v3: moved the normalization factor definition to intel_fbc.c and some > updates to comments > > Fixes: 5298eea7ed20 ("drm/i915/xe3p_lpd: use pixel normalizer for fp16 formats for FBC") > Signed-off-by: Vinod Govindapillai > --- > .../drm/i915/display/intel_display_device.h | 1 + > .../drm/i915/display/intel_display_types.h | 8 ++ > drivers/gpu/drm/i915/display/intel_fbc.c | 19 ++++- > drivers/gpu/drm/i915/display/intel_fbc.h | 4 +- > .../drm/i915/display/skl_universal_plane.c | 82 +++++++++++++++---- > .../i915/display/skl_universal_plane_regs.h | 1 - > 6 files changed, 92 insertions(+), 23 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_device.h b/drivers/gpu/drm/i915/display/intel_display_device.h > index 6c74d6b0cc48..126aa1eeeb6d 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_device.h > +++ b/drivers/gpu/drm/i915/display/intel_display_device.h > @@ -175,6 +175,7 @@ struct intel_display_platforms { > #define HAS_DSC_MST(__display) (DISPLAY_VER(__display) >= 12 && HAS_DSC(__display)) > #define HAS_FBC(__display) (DISPLAY_RUNTIME_INFO(__display)->fbc_mask != 0) > #define HAS_FBC_DIRTY_RECT(__display) (DISPLAY_VER(__display) >= 30) > +#define HAS_FBC_FP16_FORMATS(__display) (DISPLAY_VER(__display) >= 35) > #define HAS_FBC_SYS_CACHE(__display) (DISPLAY_VER(__display) >= 35 && !(__display)->platform.dgfx) > #define HAS_FPGA_DBG_UNCLAIMED(__display) (DISPLAY_INFO(__display)->has_fpga_dbg) > #define HAS_FW_BLC(__display) (DISPLAY_VER(__display) >= 3) > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h > index e6298279dc89..92bce232b2c5 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_types.h > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h > @@ -686,6 +686,14 @@ struct intel_plane_state { > unsigned long flags; > #define PLANE_HAS_FENCE BIT(0) > > + /* xe3p_lpd+ */ > + struct { > + /* In half-precision floating-point format. 0x3c00 (1.0) for fp16 formats */ > + unsigned int factor; > + /* update is needed if factor differs between old and new plane states */ > + bool needs_update; > + } pixel_normalizer; > + > struct intel_fb_view view; > > /* for legacy cursor fb unpin */ > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c > index 1f3f5237a1c2..f9474e7741c8 100644 > --- a/drivers/gpu/drm/i915/display/intel_fbc.c > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c > @@ -71,6 +71,9 @@ > > #define FBC_SYS_CACHE_ID_NONE I915_MAX_FBCS > > +/* Pixel normalization factor 1.0 in half-precision floating-point format */ > +#define NORM_FACTOR_1_0_IN_HALF_PRECISION_FP 0x3c00 > + > struct intel_fbc_funcs { > void (*activate)(struct intel_fbc *fbc); > void (*deactivate)(struct intel_fbc *fbc); > @@ -1215,13 +1218,21 @@ static bool xe3p_lpd_fbc_pixel_format_is_valid(const struct intel_plane_state *p > } > } > > -bool > -intel_fbc_is_enable_pixel_normalizer(const struct intel_plane_state *plane_state) > +unsigned int > +intel_fbc_normalization_factor(const struct intel_plane_state *plane_state) > { > struct intel_display *display = to_intel_display(plane_state); > > - return DISPLAY_VER(display) >= 35 && > - xe3p_lpd_fbc_fp16_format_is_valid(plane_state); > + /* > + * In order to have FBC for fp16 formats pixel normalizer block must be > + * active. For FP16 formats, use normalization factor as 1.0 and enable > + * the block. > + */ > + if (HAS_FBC_FP16_FORMATS(display) && > + xe3p_lpd_fbc_fp16_format_is_valid(plane_state)) > + return NORM_FACTOR_1_0_IN_HALF_PRECISION_FP; > + > + return 0; > } > > static bool pixel_format_is_valid(const struct intel_plane_state *plane_state) > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.h b/drivers/gpu/drm/i915/display/intel_fbc.h > index f0255ddae2b6..b5888e98a659 100644 > --- a/drivers/gpu/drm/i915/display/intel_fbc.h > +++ b/drivers/gpu/drm/i915/display/intel_fbc.h > @@ -56,7 +56,7 @@ void intel_fbc_prepare_dirty_rect(struct intel_atomic_state *state, > struct intel_crtc *crtc); > void intel_fbc_dirty_rect_update_noarm(struct intel_dsb *dsb, > struct intel_plane *plane); > -bool > -intel_fbc_is_enable_pixel_normalizer(const struct intel_plane_state *plane_state); > +unsigned int > +intel_fbc_normalization_factor(const struct intel_plane_state *plane_state); > > #endif /* __INTEL_FBC_H__ */ > diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c > index b3d41705448a..05c227913b8d 100644 > --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c > +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c > @@ -891,20 +891,49 @@ static void icl_plane_disable_sel_fetch_arm(struct intel_dsb *dsb, > intel_de_write_dsb(display, dsb, SEL_FETCH_PLANE_CTL(pipe, plane->id), 0); > } > > -static void x3p_lpd_plane_update_pixel_normalizer(struct intel_dsb *dsb, > - struct intel_plane *plane, > - bool enable) > +static void xe3p_lpd_plane_disable_pixel_normalizer(struct intel_dsb *dsb, > + struct intel_plane *plane) > { > struct intel_display *display = to_intel_display(plane); > enum intel_fbc_id fbc_id = skl_fbc_id_for_pipe(plane->pipe); > - u32 val; > + const struct intel_plane_state *plane_state = > + to_intel_plane_state(plane->base.state); > + > + if (!HAS_FBC_FP16_FORMATS(display)) > + return; > + > + if (!skl_plane_has_fbc(display, fbc_id, plane->id)) > + return; > + > + if (!plane_state->pixel_normalizer.factor) > + return; > + > + intel_de_write_dsb(display, dsb, > + PLANE_PIXEL_NORMALIZE(plane->pipe, plane->id), 0); > +} > + > +static void xe3p_lpd_plane_update_pixel_normalizer(struct intel_dsb *dsb, > + struct intel_plane *plane) > +{ > + struct intel_display *display = to_intel_display(plane); > + enum intel_fbc_id fbc_id = skl_fbc_id_for_pipe(plane->pipe); > + const struct intel_plane_state *plane_state = > + to_intel_plane_state(plane->base.state); > + u32 val = 0; > + > + if (!HAS_FBC_FP16_FORMATS(display)) > + return; > > - /* Only HDR planes have pixel normalizer and don't matter if no FBC */ > + /* Only HDR planes have pixel normalizer and don't matter if FBC is fused off */ > if (!skl_plane_has_fbc(display, fbc_id, plane->id)) > return; > > - val = enable ? PLANE_PIXEL_NORMALIZE_NORM_FACTOR(PLANE_PIXEL_NORMALIZE_NORM_FACTOR_1_0) | > - PLANE_PIXEL_NORMALIZE_ENABLE : 0; > + if (!plane_state->pixel_normalizer.needs_update) > + return; > + > + if (plane_state->pixel_normalizer.factor) > + val = PLANE_PIXEL_NORMALIZE_NORM_FACTOR(plane_state->pixel_normalizer.factor) | > + PLANE_PIXEL_NORMALIZE_ENABLE; > > intel_de_write_dsb(display, dsb, > PLANE_PIXEL_NORMALIZE(plane->pipe, plane->id), val); > @@ -926,8 +955,7 @@ icl_plane_disable_arm(struct intel_dsb *dsb, > > icl_plane_disable_sel_fetch_arm(dsb, plane, crtc_state); > > - if (DISPLAY_VER(display) >= 35) > - x3p_lpd_plane_update_pixel_normalizer(dsb, plane, false); > + xe3p_lpd_plane_disable_pixel_normalizer(dsb, plane); > > intel_de_write_dsb(display, dsb, PLANE_CTL(pipe, plane_id), 0); > intel_de_write_dsb(display, dsb, PLANE_SURF(pipe, plane_id), 0); > @@ -1674,13 +1702,7 @@ icl_plane_update_arm(struct intel_dsb *dsb, > > intel_color_plane_commit_arm(dsb, plane_state); > > - /* > - * In order to have FBC for fp16 formats pixel normalizer block must be > - * active. Check if pixel normalizer block need to be enabled for FBC. > - * If needed, use normalization factor as 1.0 and enable the block. > - */ > - if (intel_fbc_is_enable_pixel_normalizer(plane_state)) > - x3p_lpd_plane_update_pixel_normalizer(dsb, plane, true); > + xe3p_lpd_plane_update_pixel_normalizer(dsb, plane); > > /* > * The control register self-arms if the plane was previously > @@ -2350,6 +2372,32 @@ static void clip_damage(struct intel_plane_state *plane_state) > drm_rect_intersect(damage, &src); > } > > +static void check_pixel_normalizer(struct intel_plane_state *plane_state) > +{ > + struct intel_display *display = to_intel_display(plane_state); > + struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane); > + struct intel_atomic_state *state = > + to_intel_atomic_state(plane_state->uapi.state); > + const struct intel_plane_state *old_plane_state = > + intel_atomic_get_old_plane_state(state, plane); > + > + if (!HAS_FBC_FP16_FORMATS(display)) > + return; > + > + plane_state->pixel_normalizer.factor = > + intel_fbc_normalization_factor(plane_state); > + > + /* > + * In case of no old state to compare, better to force update the pixel > + * normalizer settings. > + */ > + plane_state->pixel_normalizer.needs_update = true; > + if (old_plane_state && old_plane_state->hw.fb) > + plane_state->pixel_normalizer.needs_update = > + plane_state->pixel_normalizer.factor != > + intel_fbc_normalization_factor(old_plane_state); > +} > + > static int skl_plane_check(struct intel_crtc_state *crtc_state, > struct intel_plane_state *plane_state) > { > @@ -2400,6 +2448,8 @@ static int skl_plane_check(struct intel_crtc_state *crtc_state, > > check_protection(plane_state); > > + check_pixel_normalizer(plane_state); > + > /* HW only has 8 bits pixel precision, disable plane if invisible */ > if (!(plane_state->hw.alpha >> 8)) { > plane_state->uapi.visible = false; > diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane_regs.h b/drivers/gpu/drm/i915/display/skl_universal_plane_regs.h > index 6fd4da9f63cf..651f3557b576 100644 > --- a/drivers/gpu/drm/i915/display/skl_universal_plane_regs.h > +++ b/drivers/gpu/drm/i915/display/skl_universal_plane_regs.h > @@ -580,6 +580,5 @@ > #define PLANE_PIXEL_NORMALIZE_ENABLE REG_BIT(31) > #define PLANE_PIXEL_NORMALIZE_NORM_FACTOR_MASK REG_GENMASK(15, 0) > #define PLANE_PIXEL_NORMALIZE_NORM_FACTOR(val) REG_FIELD_PREP(PLANE_PIXEL_NORMALIZE_NORM_FACTOR_MASK, (val)) > -#define PLANE_PIXEL_NORMALIZE_NORM_FACTOR_1_0 0x3c00 > > #endif /* __SKL_UNIVERSAL_PLANE_REGS_H__ */ > -- > 2.43.0 -- Ville Syrjälä Intel