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 X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB55EC433E0 for ; Tue, 9 Feb 2021 15:36:12 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 536D6601FD for ; Tue, 9 Feb 2021 15:36:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 536D6601FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C95B06EB5E; Tue, 9 Feb 2021 15:36:11 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id EA91E6EB67; Tue, 9 Feb 2021 15:36:10 +0000 (UTC) IronPort-SDR: 29RSp6vMIdQaKblOVPbCQ7bkzPpMjDWsNF39QoXomQI+cADV/EJ9Mn83BMXqkOuBJsBKUh2csk 9lNPueD3YQ5w== X-IronPort-AV: E=McAfee;i="6000,8403,9889"; a="179339839" X-IronPort-AV: E=Sophos;i="5.81,165,1610438400"; d="scan'208";a="179339839" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Feb 2021 07:36:10 -0800 IronPort-SDR: Sea8NHAhGA9jZbHTingLKer22K0lsSEL5F8qjZEtJ6c0R3HRMAIUn6WpXgVP95rUBTp+0IBmqQ +anFK+cXiDbw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,165,1610438400"; d="scan'208";a="488186228" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by fmsmga001.fm.intel.com with SMTP; 09 Feb 2021 07:36:08 -0800 Received: by stinkbox (sSMTP sendmail emulation); Tue, 09 Feb 2021 17:36:07 +0200 Date: Tue, 9 Feb 2021 17:36:07 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Daniel Vetter Message-ID: References: <20210209101523.2954281-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210209101523.2954281-1-daniel.vetter@ffwll.ch> X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH] drm/vblank: Document drm_crtc_vblank_restore constraints X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , Intel Graphics Development , DRI Development Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Feb 09, 2021 at 11:15:23AM +0100, Daniel Vetter wrote: > I got real badly confused when trying to review a fix from Ville for > this. Let's try to document better what's required for this, and check > the minimal settings at runtime - we can't check ofc that there's > indeed no races in the driver callback. > = > Also noticed that the drm_vblank_restore version is unused, so lets > unexport that while at it. > = > Cc: Ville Syrjala > Signed-off-by: Daniel Vetter > --- > drivers/gpu/drm/drm_vblank.c | 25 ++++++++++--------------- > include/drm/drm_vblank.h | 1 - > 2 files changed, 10 insertions(+), 16 deletions(-) > = > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > index c914b14cfb43..05f4d4c078fd 100644 > --- a/drivers/gpu/drm/drm_vblank.c > +++ b/drivers/gpu/drm/drm_vblank.c > @@ -1471,20 +1471,7 @@ void drm_crtc_vblank_on(struct drm_crtc *crtc) > } > EXPORT_SYMBOL(drm_crtc_vblank_on); > = > -/** > - * drm_vblank_restore - estimate missed vblanks and update vblank count. > - * @dev: DRM device > - * @pipe: CRTC index > - * > - * Power manamement features can cause frame counter resets between vbla= nk > - * disable and enable. Drivers can use this function in their > - * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblan= ks since > - * the last &drm_crtc_funcs.disable_vblank using timestamps and update t= he > - * vblank counter. > - * > - * This function is the legacy version of drm_crtc_vblank_restore(). > - */ > -void drm_vblank_restore(struct drm_device *dev, unsigned int pipe) > +static void drm_vblank_restore(struct drm_device *dev, unsigned int pipe) > { > ktime_t t_vblank; > struct drm_vblank_crtc *vblank; > @@ -1520,7 +1507,6 @@ void drm_vblank_restore(struct drm_device *dev, uns= igned int pipe) > 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 missed vblanks and update vblank c= ount. > @@ -1531,9 +1517,18 @@ EXPORT_SYMBOL(drm_vblank_restore); > * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblan= ks since > * the last &drm_crtc_funcs.disable_vblank using timestamps and update t= he > * vblank counter. > + * > + * Note that drivers must have race-free high-precision timestamping sup= port, > + * i.e. &drm_crtc_funcs.get_vblank_timestamp must be hooked up and > + * &drm_driver.vblank_disable_immediate must be set to indicate the > + * time-stamping functions are race-free against vblank hardware counter > + * increments. Looks good. Might prevent someone from shooting themselves in the foot. Reviewed-by: Ville Syrj=E4l=E4 > */ > void drm_crtc_vblank_restore(struct drm_crtc *crtc) > { > + WARN_ON_ONCE(!crtc->funcs->get_vblank_timestamp); > + WARN_ON_ONCE(!crtc->dev->vblank_disable_immediate); > + > drm_vblank_restore(crtc->dev, drm_crtc_index(crtc)); > } > EXPORT_SYMBOL(drm_crtc_vblank_restore); > diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h > index dd125f8c766c..733a3e2d1d10 100644 > --- a/include/drm/drm_vblank.h > +++ b/include/drm/drm_vblank.h > @@ -247,7 +247,6 @@ 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); > = > void drm_calc_timestamping_constants(struct drm_crtc *crtc, > -- = > 2.30.0 -- = Ville Syrj=E4l=E4 Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx