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 932EFC021B1 for ; Wed, 19 Feb 2025 18:47:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 457B110E4AD; Wed, 19 Feb 2025 18:47:30 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="mubhQwmh"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2D52F10E36A for ; Wed, 19 Feb 2025 18:47:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1739990849; x=1771526849; h=date:message-id:from:to:cc:subject:in-reply-to: references:mime-version; bh=/J7lwu3hiqaWF9SwmBXurd+bZHjNOsMyaKhZTjdODD0=; b=mubhQwmhMEf07XhK+e/yZcpqHtNmbw3UUgKKXi4IHl8QLasZdprGqTfQ dvQLo9o7f1ApqTeiaIy82ugOE4AwtEWcHBVOUXSm+bE/u0MePd59QmuH/ NNbcWVBHOVHXuLquzSziiWHBXYFX0S/AzecWeO6cgaMBrf+ulB7zdVv0/ WQrRWLzawQ4aClut/2ZdF1CJekCF5a28DMEQ7ffSvFrllzc4amlMqLLkF 4XJBqePuIjrH6joQOGUkfzMAk+bULuXE7APPPgKl/JCsWXyJYM3JGe6b6 ptvRInYzScgSa7qAevSAjmlWSZziZlftCghZdeNvfnx/0SIafa4l/cPdn g==; X-CSE-ConnectionGUID: Gr9+hBLKQ52NN7XXC72qrQ== X-CSE-MsgGUID: 4DnmBvixRu6QGpUYI/E8dA== X-IronPort-AV: E=McAfee;i="6700,10204,11350"; a="28340099" X-IronPort-AV: E=Sophos;i="6.13,299,1732608000"; d="scan'208";a="28340099" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Feb 2025 10:47:29 -0800 X-CSE-ConnectionGUID: mewmO5JLQ+2GsarckISh+A== X-CSE-MsgGUID: +Uh0dRPrRrS9jcYKe5g30w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.13,299,1732608000"; d="scan'208";a="145642143" Received: from orsosgc001.jf.intel.com (HELO orsosgc001.intel.com) ([10.165.21.142]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Feb 2025 10:47:22 -0800 Date: Wed, 19 Feb 2025 10:47:19 -0800 Message-ID: <85seo9ojpk.wl-ashutosh.dixit@intel.com> From: "Dixit, Ashutosh" To: Harish Chegondi Cc: Subject: Re: [PATCH v10 5/8] drm/xe/eustall: Add support to handle dropped EU stall data In-Reply-To: <42c8cecda3f50374ed90fe2911e7f5a3523e157b.1739906138.git.harish.chegondi@intel.com> References: <42c8cecda3f50374ed90fe2911e7f5a3523e157b.1739906138.git.harish.chegondi@intel.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?ISO-8859-4?Q?Goj=F2?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/28.2 (x86_64-redhat-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII 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, 18 Feb 2025 11:53:55 -0800, Harish Chegondi wrote: > > If the user space doesn't read the EU stall data fast enough, > it is possible that the EU stall data buffer can get filled, > and if the hardware wants to write more data, it simply drops > data due to unavailable buffer space. In that case, hardware > sets a bit in a register. If the driver detects data drop, > the driver read() returns -EIO error to let the user space > know that HW has dropped data. The -EIO error is returned > even if there is EU stall data in the buffer. A subsequent > read by the user space returns the remaining EU stall data. > > v10: Reverted the changes back to v8: > Clear the drop bits only after reading the data. I think I am ok with this patch as is. Unless we agree to drop data in the driver (which I had proposed but you had rejected), I don't think we can do a lot more without really complicating things. So I don't want to go there yet. But lets first go through the coments on PATCH v10 4/8. Once we resolve the locking issue raised there, I will review this patch again and hopefully R-b it. See if you need to send a new revision of the series. Thanks. -- Ashutosh