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 4FC9CD78336 for ; Mon, 2 Dec 2024 16:28:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1686F10E7BB; Mon, 2 Dec 2024 16:28:51 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Zp6Nf7Tt"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6D45510E7BB for ; Mon, 2 Dec 2024 16:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1733156930; x=1764692930; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=3oIE5XBW26oRog8Lj0vQ+BFKlk+v9q8gkLJS1Pzafhc=; b=Zp6Nf7Tt0YdOS0lp6+swlHxdCklcPmTRyN111Xu4e8Zac/yk9ivVMmMM WO1ABBNbap7sHiL+On8WSEqISGjFVTm35qV5ZpQQYDyNam0ty5kJUtP7R EL/eSufoGBc81yZX5HjULxYgZ1UJrtivcht3v2275+egg1tEF0iMYMYVY MGzBnyaPaau3dr5aR1FJGnrzHdH0Gob9Wgf1BCBs3/5wLdqNLrkpGquEJ 24yOZq/BxNl8325H6+TFlb/+CKdNfznYFz7wsVmC+0IjHjLIN9cV0i+Hq O0jtMKElxxTzba9TnlEj1qUR2u5rHKydVqKR+OYLNxgBpwrI91eZEKo6o w==; X-CSE-ConnectionGUID: pMDBf4klT7m24BGVgeOcQQ== X-CSE-MsgGUID: nSkB+eJnQuWSOtDP8hvpog== X-IronPort-AV: E=McAfee;i="6700,10204,11274"; a="43816651" X-IronPort-AV: E=Sophos;i="6.12,202,1728975600"; d="scan'208";a="43816651" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2024 08:28:49 -0800 X-CSE-ConnectionGUID: 5J5LLFTXQ2i5V6UkGpMNBA== X-CSE-MsgGUID: HY8ltekMQpi3PeRwdQITlg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,202,1728975600"; d="scan'208";a="93053645" Received: from dalessan-mobl3.ger.corp.intel.com (HELO [10.245.244.79]) ([10.245.244.79]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2024 08:28:48 -0800 Message-ID: <602c7ab7-cab9-4790-a67c-306b23a75f23@intel.com> Date: Mon, 2 Dec 2024 16:28:45 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/xe/display: fix ttm_bo_access() usage To: =?UTF-8?Q?Thomas_Hellstr=C3=B6m?= , intel-xe@lists.freedesktop.org Cc: Matthew Brost , Jani Nikula References: <20241202154123.76887-2-matthew.auld@intel.com> Content-Language: en-GB From: Matthew Auld In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed 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" On 02/12/2024 15:56, Thomas Hellström wrote: > On Mon, 2024-12-02 at 15:41 +0000, Matthew Auld wrote: >> ttm_bo_access() returns the size on success. Account for that >> otherwise >> the caller incorrectly thinks this is an error in >> intel_atomic_prepare_plane_clear_colors(). >> >> Fixes: b6308aaa24a7 ("drm/xe/display: Update intel_bo_read_from_page >> to use ttm_bo_access") >> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/3661 >> Signed-off-by: Matthew Auld >> Cc: Thomas Hellström >> Cc: Matthew Brost >> Cc: Jani Nikula >> --- >>  drivers/gpu/drm/xe/display/intel_bo.c | 7 ++++++- >>  1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/xe/display/intel_bo.c >> b/drivers/gpu/drm/xe/display/intel_bo.c >> index 43141964f6f2..b2a8d06cc78a 100644 >> --- a/drivers/gpu/drm/xe/display/intel_bo.c >> +++ b/drivers/gpu/drm/xe/display/intel_bo.c >> @@ -40,8 +40,13 @@ int intel_bo_fb_mmap(struct drm_gem_object *obj, >> struct vm_area_struct *vma) >>  int intel_bo_read_from_page(struct drm_gem_object *obj, u64 offset, >> void *dst, int size) >>  { >>   struct xe_bo *bo = gem_to_xe_bo(obj); >> + int ret; >> >> - return ttm_bo_access(&bo->ttm, offset, dst, size, 0); >> + ret = ttm_bo_access(&bo->ttm, offset, dst, size, 0); >> + if (ret == size) >> + ret = 0; >> + >> + return ret; >>  } >> > > Looking at how callers are using struct vm_operations_struct::access() > it looks possible that 0 <= ret < size, indicating the number of bytes > actually processed. > > Now since ttm_bo_access() is actually a helper to implement the above, > we strictly don't have to follow that for its interface, but I think it > makes sense to assert that ret is either == size or something negative. > Ideas? hmm, what about if we add something like: +int xe_bo_read(struct xe_bo *bo, u64 offset, void *dst, int size) +{ + int ret; + + ret = ttm_bo_access(&bo->ttm, offset, dst, size, 0); + if (!(ret < 0) && ret != size) + ret = -EIO; + else if (!(ret < 0)) + ret = 0; + + return ret; +} And then both callers use that? > > /Thomas > > > >>  struct intel_frontbuffer *intel_bo_get_frontbuffer(struct >> drm_gem_object *obj) >