From patchwork Fri Aug 12 06:25:20 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: akash.goel@intel.com X-Patchwork-Id: 9276397 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CA80660CDC for ; Fri, 12 Aug 2016 06:12:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BC2302888A for ; Fri, 12 Aug 2016 06:12:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B0B5F2888C; Fri, 12 Aug 2016 06:12:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 78EC12888B for ; Fri, 12 Aug 2016 06:12:17 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9F1216EA73; Fri, 12 Aug 2016 06:12:15 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id B36216EA6B for ; Fri, 12 Aug 2016 06:12:10 +0000 (UTC) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP; 11 Aug 2016 23:12:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,508,1464678000"; d="scan'208";a="154643723" Received: from akashgoe-desktop.iind.intel.com ([10.223.82.36]) by fmsmga004.fm.intel.com with ESMTP; 11 Aug 2016 23:12:09 -0700 From: akash.goel@intel.com To: intel-gfx@lists.freedesktop.org Date: Fri, 12 Aug 2016 11:55:20 +0530 Message-Id: <1470983123-22127-18-git-send-email-akash.goel@intel.com> X-Mailer: git-send-email 1.9.2 In-Reply-To: <1470983123-22127-1-git-send-email-akash.goel@intel.com> References: <1470983123-22127-1-git-send-email-akash.goel@intel.com> Cc: Akash Goel Subject: [Intel-gfx] [PATCH 17/20] drm/i915: Use uncached(WC) mapping for acessing the GuC log buffer X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP From: Akash Goel Host needs to sample the GuC log buffer on every flush interrupt from GuC. To ensure that we always get the up-to-date data from log buffer, its better to access the buffer through an uncached CPU mapping. Also the way buffer is accessed from GuC & Host side, manually doing cache flush may not be effective always if cached CPU mapping is used. Though there could be some performance implication with Uncached read, but reliability of data will be ensured. v2: Rebase. v3: Rebase. Signed-off-by: Akash Goel Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_guc_submission.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index 1d58d36..1818343 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -1002,8 +1002,6 @@ static void guc_read_update_log_buffer(struct intel_guc *guc) dst_data_ptr += buffer_size; } - /* FIXME: invalidate/flush for log buffer needed */ - /* Update the read pointer in the shared log buffer */ log_buffer_state->read_ptr = write_offset; @@ -1177,8 +1175,11 @@ static int guc_create_log_extras(struct intel_guc *guc) return 0; if (!guc->log.buf_addr) { - /* Create a vmalloc mapping of log buffer pages */ - vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WB); + /* Create a WC (Uncached for read) vmalloc mapping of log + * buffer pages, so that we can directly get the data + * (up-to-date) from memory. + */ + vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WC); if (IS_ERR(vaddr)) { ret = PTR_ERR(vaddr); DRM_ERROR("Couldn't map log buffer pages %d\n", ret);