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 ED3FCF9D0FD for ; Wed, 15 Apr 2026 00:21:12 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D65BB10E096; Wed, 15 Apr 2026 00:21:11 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="RjhislDU"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) by gabe.freedesktop.org (Postfix) with ESMTPS id DAC7810E091; Wed, 15 Apr 2026 00:21:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776212470; x=1807748470; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=SFctM2xlOMoI8Vbpi8AHmWKdQr2mcaddcQzz+Tz1Zjc=; b=RjhislDUxexVsFLCUgbkTqaiMZC91wui855gL9eBivYx7rfdpqJif4hG 9NRRb3gp6kNDS4hFqRwnQcQu+uzILL2Xl3EVVPrMx7iu5hjzru+qO7HEg WofZHxaiZUjFnLK8TQY8TEOXk9mD0W48pMYpFPet3GY4AZ+x0BXMl3KRo M4XMv8gy9Z2yMtm3qMsgTeV5Wrt8qnIo1UwAIRJBNq0kxNIcHpfQqtYqM q4SGBr7LzEGJW6qM/XUoGdPz1M7LOOBm4/9Tzf+/X0jYGVW7b6BByGnB9 rSht8wZkJ/fEcjjm0qMaJ7v8nzC38L/r+yZ3hDIapjw1PNgbwZrWCWZ1k w==; X-CSE-ConnectionGUID: PTQFQhS1QriNBwkWo60mCA== X-CSE-MsgGUID: XzbhD1/5TeWCUgifPb/7UQ== X-IronPort-AV: E=McAfee;i="6800,10657,11759"; a="88261133" X-IronPort-AV: E=Sophos;i="6.23,179,1770624000"; d="scan'208";a="88261133" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2026 17:21:09 -0700 X-CSE-ConnectionGUID: ajnDZTSCSJivw4lUe/9FTQ== X-CSE-MsgGUID: T5QSvp7MScWTzvnC331yxA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,179,1770624000"; d="scan'208";a="268228708" Received: from vsrini4-xps-8920.iind.intel.com ([10.223.167.75]) by orviesa001.jf.intel.com with ESMTP; 14 Apr 2026 17:21:08 -0700 From: Vidya Srinivas To: intel-gfx@lists.freedesktop.org Cc: intel-xe@lists.freedesktop.org, uma.shankar@intel.com, jani.nikula@intel.com, Vidya Srinivas Subject: [PATCH] [RFC]: drm/i915/display: Use ceiling division for NV12 UV surface offset calculation Date: Wed, 15 Apr 2026 05:45:53 +0530 Message-ID: <20260415001553.181329-1-vidya.srinivas@intel.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260411171521.162189-1-vidya.srinivas@intel.com> References: <20260411171521.162189-1-vidya.srinivas@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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" For LNL+, odd source size and panning for YUV 422/420 surfaces is supported. However, it requires the UV (chroma) surface Start X/Y and width/height to be calculated as ceiling(half of Y plane value) rather than floor. The current code uses (>> 17) which combines the U16.16 fixed-point to integer conversion (>> 16) with a divide-by-2 for chroma subsampling (>> 1) into a single floor division. For odd Y plane values this produces an off-by-one error in the UV plane offset. On Android systems we see PLANE ATS fault when NV12 overlays are used with odd source dimensions: [ 126.854200] xe 0000:00:02.0: [drm:intel_atomic_setup_scaler [xe]] [CRTC:148:pipe A] attached scaler id 0.0 to PLANE:33 [ 126.854617] xe 0000:00:02.0: [drm:skl_update_scaler [xe]] [CRTC:148:pipe A] scaler_user index 0.0: staged scaling request for 1279x719->1340x753 [ 126.854837] xe 0000:00:02.0: [drm:intel_plane_atomic_check [xe]] UV plane [PLANE:33:plane 1A] using Y plane [PLANE:123:plane 4A] [ 126.854926] xe 0000:00:02.0: [drm] *ERROR* [CRTC:148:pipe A] PLANE ATS fault With Y plane width 1279: floor(1279/2) = 639 (current) ceil(1279/2) = 640 (required) Use DIV_ROUND_UP(value, 1 << 17) for the ceiling division of the U16.16 fixed-point source coordinates, preserving sub-pixel precision. This is a no-op for even values since ceiling and floor are equal when the dividend is even. v2: Use DIV_ROUND_UP(value, 1 << 17) to preserve sub-pixel precision while making the ceiling division readable (Jani, Uma) Signed-off-by: Vidya Srinivas --- drivers/gpu/drm/i915/display/skl_universal_plane.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c index 7a9d494334b5..1de79ff65253 100644 --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c @@ -2139,10 +2139,16 @@ static int skl_check_nv12_aux_surface(struct intel_plane_state *plane_state) int min_height = intel_plane_min_height(plane, fb, uv_plane, rotation); int max_width = intel_plane_max_width(plane, fb, uv_plane, rotation); int max_height = intel_plane_max_height(plane, fb, uv_plane, rotation); - int x = plane_state->uapi.src.x1 >> 17; - int y = plane_state->uapi.src.y1 >> 17; - int w = drm_rect_width(&plane_state->uapi.src) >> 17; - int h = drm_rect_height(&plane_state->uapi.src) >> 17; + + /* + * LNL+ UV surface start/size = + * ceiling(half of Y plane start/size). Use ceiling division + * unconditionally; it is a no-op for even values. + */ + int x = DIV_ROUND_UP(plane_state->uapi.src.x1, 1 << 17); + int y = DIV_ROUND_UP(plane_state->uapi.src.y1, 1 << 17); + int w = DIV_ROUND_UP(drm_rect_width(&plane_state->uapi.src), 1 << 17); + int h = DIV_ROUND_UP(drm_rect_height(&plane_state->uapi.src), 1 << 17); u32 offset; /* FIXME not quite sure how/if these apply to the chroma plane */ -- 2.45.2