From patchwork Wed Aug 17 10:14:16 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: 9285493 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 0E900600CB for ; Wed, 17 Aug 2016 10:01:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F2D3F2880E for ; Wed, 17 Aug 2016 10:01:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E7A872882C; Wed, 17 Aug 2016 10:01:21 +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 A99582880E for ; Wed, 17 Aug 2016 10:01:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 322C76E7E7; Wed, 17 Aug 2016 10:01:21 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTP id 766176E7E6 for ; Wed, 17 Aug 2016 10:01:04 +0000 (UTC) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP; 17 Aug 2016 03:01:04 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,529,1464678000"; d="scan'208";a="749856339" Received: from akashgoe-desktop.iind.intel.com ([10.223.82.36]) by FMSMGA003.fm.intel.com with ESMTP; 17 Aug 2016 03:01:03 -0700 From: akash.goel@intel.com To: intel-gfx@lists.freedesktop.org Date: Wed, 17 Aug 2016 15:44:16 +0530 Message-Id: <1471428859-10339-17-git-send-email-akash.goel@intel.com> X-Mailer: git-send-email 1.9.2 In-Reply-To: <1471428859-10339-1-git-send-email-akash.goel@intel.com> References: <1471428859-10339-1-git-send-email-akash.goel@intel.com> Cc: Akash Goel Subject: [Intel-gfx] [PATCH 16/19] 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. v4: 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 5a302fe..3e8af71 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -1126,8 +1126,6 @@ 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; @@ -1196,8 +1194,11 @@ 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.vma->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.vma->obj, I915_MAP_WC); if (IS_ERR(vaddr)) { ret = PTR_ERR(vaddr); DRM_ERROR("Couldn't map log buffer pages %d\n", ret);