From patchwork Fri Jan 12 21:57:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dhinakaran Pandiyan X-Patchwork-Id: 10161779 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 21A9160327 for ; Fri, 12 Jan 2018 21:57:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 136C128A55 for ; Fri, 12 Jan 2018 21:57:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0871128A61; Fri, 12 Jan 2018 21:57:58 +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=unavailable 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 7549028A55 for ; Fri, 12 Jan 2018 21:57:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 62FF46E981; Fri, 12 Jan 2018 21:57:36 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6646A6E56A; Fri, 12 Jan 2018 21:57:29 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Jan 2018 13:57:29 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,350,1511856000"; d="scan'208";a="18787076" Received: from dk-thinkpad-x260.jf.intel.com (HELO localhost.localdomain) ([10.54.75.38]) by FMSMGA003.fm.intel.com with ESMTP; 12 Jan 2018 13:57:28 -0800 From: Dhinakaran Pandiyan To: intel-gfx@lists.freedesktop.org Date: Fri, 12 Jan 2018 13:57:06 -0800 Message-Id: <20180112215707.3084-4-dhinakaran.pandiyan@intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180112215707.3084-1-dhinakaran.pandiyan@intel.com> References: <20180112215707.3084-1-dhinakaran.pandiyan@intel.com> MIME-Version: 1.0 Cc: Daniel Vetter , =?UTF-8?q?Michel=20D=C3=A4nzer?= , dri-devel@lists.freedesktop.org, Dhinakaran Pandiyan , rodrigo.vivi@intel.com Subject: [Intel-gfx] [PATCH 4/5] drm/vblank: Restoring vblank counts after device PM events. 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP The HW frame counter can get reset if device enters a low power state after vblank interrupts were disabled. This messes up any following vblank count update as a negative diff (huge unsigned diff) is calculated from the HW frame counter change. We cannot ignore negative diffs altogther as there could be legitimate wrap arounds. So, allow drivers to update vblank->count with missed vblanks for the time interrupts were disabled. This is similar to _crtc_vblank_on() except that vblanks interrupts are not enabled at the end as this function is expected to be called from the driver _enable_vblank() vfunc. v2: drm_crtc_vblank_restore should take crtc as arg. (Chris) Add docs and sprinkle some asserts. Cc: Daniel Vetter Cc: Chris Wilson Cc: Michel Dänzer Signed-off-by: Dhinakaran Pandiyan Reviewed-by: Rodrigo Vivi --- drivers/gpu/drm/drm_vblank.c | 59 ++++++++++++++++++++++++++++++++++++++++++++ include/drm/drm_vblank.h | 2 ++ 2 files changed, 61 insertions(+) diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 2559d2d7b907..2690966694f0 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -1237,6 +1237,65 @@ void drm_crtc_vblank_on(struct drm_crtc *crtc) } EXPORT_SYMBOL(drm_crtc_vblank_on); +/** + * drm_vblank_restore - estimated vblanks using timestamps and update it. + * + * Power manamement features can cause frame counter resets between vblank + * disable and enable. Drivers can then use this function in their + * &drm_crtc_funcs.enable_vblank implementation to estimate the vblanks since + * the last &drm_crtc_funcs.disable_vblank. + * + * This function is the legacy version of drm_crtc_vblank_restore(). + */ +void drm_vblank_restore(struct drm_device *dev, unsigned int pipe) +{ + ktime_t t_vblank; + struct drm_vblank_crtc *vblank; + int framedur_ns; + u64 diff_ns; + u32 cur_vblank, diff = 1; + int count = DRM_TIMESTAMP_MAXRETRIES; + + if (WARN_ON(pipe >= dev->num_crtcs)) + return; + + assert_spin_locked(&dev->vbl_lock); + assert_spin_locked(&dev->vblank_time_lock); + + vblank = &dev->vblank[pipe]; + WARN_ONCE((drm_debug & DRM_UT_VBL) && !vblank->framedur_ns, + "Cannot compute missed vblanks without frame duration\n"); + framedur_ns = vblank->framedur_ns; + + do { + cur_vblank = __get_vblank_counter(dev, pipe); + drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false); + } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0); + + diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time)); + if (framedur_ns) + diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns); + + + DRM_DEBUG_VBL("missed %d vblanks in %lld ns, frame duration=%d ns, hw_diff=%d\n", + diff, diff_ns, framedur_ns, cur_vblank - vblank->last); + store_vblank(dev, pipe, diff, t_vblank, cur_vblank); +} +EXPORT_SYMBOL(drm_vblank_restore); + +/** + * drm_crtc_vblank_restore - estimate vblanks using timestamps and update it. + * Power manamement features can cause frame counter resets between vblank + * disable and enable. Drivers can then use this function in their + * &drm_crtc_funcs.enable_vblank implementation to estimate the vblanks since + * the last &drm_crtc_funcs.disable_vblank. + */ +void drm_crtc_vblank_restore(struct drm_crtc *crtc) +{ + drm_vblank_restore(crtc->dev, drm_crtc_index(crtc)); +} +EXPORT_SYMBOL(drm_crtc_vblank_restore); + static void drm_legacy_vblank_pre_modeset(struct drm_device *dev, unsigned int pipe) { diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h index a4c3b0a0a197..16d46e2a6854 100644 --- a/include/drm/drm_vblank.h +++ b/include/drm/drm_vblank.h @@ -180,6 +180,8 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc); void drm_crtc_vblank_reset(struct drm_crtc *crtc); void drm_crtc_vblank_on(struct drm_crtc *crtc); u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc); +void drm_vblank_restore(struct drm_device *dev, unsigned int pipe); +void drm_crtc_vblank_restore(struct drm_crtc *crtc); bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, unsigned int pipe, int *max_error,