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=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 DA7FEC433E1 for ; Mon, 10 Aug 2020 12:51:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AAEFD2075F for ; Mon, 10 Aug 2020 12:51:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="Ynhhm1/2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726637AbgHJMvI (ORCPT ); Mon, 10 Aug 2020 08:51:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726465AbgHJMvG (ORCPT ); Mon, 10 Aug 2020 08:51:06 -0400 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1B41C061756 for ; Mon, 10 Aug 2020 05:51:06 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id l2so8048465wrc.7 for ; Mon, 10 Aug 2020 05:51:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=SCk9i3sWSgkWyg6YFOJHzr++ebfH7R3kDFAt5TmtoX8=; b=Ynhhm1/2yY4ztKsKdmw/j1iwW3q009I0jRUbMuq9LZANkuEOO1IXasxWYli1lB/EKU Ve6EuHB/7SmgCmkYt9b3XFPNsC5LGpXARCGJqCdxHaeG8lx5BbIldQuUK8U2diul/waV 4IvzCdT+Jw3aV69Ut16wgePjx7pnBoXO3TTPQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=SCk9i3sWSgkWyg6YFOJHzr++ebfH7R3kDFAt5TmtoX8=; b=ULetOQ2VVjQzBMxAZX26ZPj9pwgiW4EfbQurlB11jufO/PPXnymUMPuj7uqppvevAR fyLnpreiQgf6dt9ZzQe7AQZCyENlg4EC+klGoDNrN57N/kQaZdHSKmJPDcljSCl36BiD TTkvzp8vyIyLh560W/vQSoSwGgXKvMEN0GpKdc/Nj98/wAFPLxcbeYOE+NMoFztZHFu1 r4M68dGKu4q4to8N5tMzRUGBhqDZY86VtVpOHdBPzz3FQkNm17EBnwDsnwX66AR/TOSa GZ9/LfwraWTqOPPlRZdjTGnS0z9bR3fEnPxE3fuyuuF+lZfRCGbPhuhcSQKmDDRhuFyF +i/A== X-Gm-Message-State: AOAM533QQhl7gT89ZCjr8KbQjfc/5Jun9dE/5XphQZGHu934dVoGYLTy qX6c+yiHUxTCchB/E6k/U+sZPw== X-Google-Smtp-Source: ABdhPJyMU0d/6EbcBph/o2e0VviOrZzAdljVt2A/AspWDgYTr8anSDL/syByK7rh0S1Q+OIlPU8tyg== X-Received: by 2002:adf:f8d2:: with SMTP id f18mr24134081wrq.261.1597063865196; Mon, 10 Aug 2020 05:51:05 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id g70sm22140560wmg.24.2020.08.10.05.51.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Aug 2020 05:51:04 -0700 (PDT) Date: Mon, 10 Aug 2020 14:51:02 +0200 From: Daniel Vetter To: Melissa Wen Cc: Rodrigo Siqueira , Haneen Mohammed , Daniel Vetter , David Airlie , Rodrigo Siqueira , Sidong Yang , twoerner@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel-usp@googlegroups.com Subject: Re: [PATCH v3] drm/vkms: guarantee vblank when capturing crc Message-ID: <20200810125102.GO2352366@phenom.ffwll.local> Mail-Followup-To: Melissa Wen , Rodrigo Siqueira , Haneen Mohammed , David Airlie , Rodrigo Siqueira , Sidong Yang , twoerner@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel-usp@googlegroups.com References: <20200808120900.pudwwrfz44g3rqx7@smtp.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200808120900.pudwwrfz44g3rqx7@smtp.gmail.com> X-Operating-System: Linux phenom 5.7.0-1-amd64 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 08, 2020 at 09:09:00AM -0300, Melissa Wen wrote: > VKMS needs vblank interrupts enabled to capture CRC. When vblank is > disabled, tests like kms_cursor_crc and kms_pipe_crc_basic getting stuck > waiting for a capture that will not occur until vkms wakes up. This patch > adds a helper to set composer and ensure that vblank remains enabled as > long as the CRC capture is needed. > > It clears the execution of the following kms_cursor_crc subtests: > 1. pipe-A-cursor-[size,alpha-opaque, NxN-(on-screen, off-screen, sliding, > random, fast-moving])] - successful when running individually. > 2. pipe-A-cursor-dpms passes again > 3. pipe-A-cursor-suspend also passes > > The issue was initially tracked in the sequential execution of IGT > kms_cursor_crc subtests: when running the test sequence or one of its > subtests twice, the odd execs complete and the pairs get stuck in an > endless wait. In the IGT code, calling a wait_for_vblank on preparing for > CRC capture prevented the busy-wait. But the problem persisted in the > pipe-A-cursor-dpms and -suspend subtests. > > Checking the history, the pipe-A-cursor-dpms subtest was successful when, > in vkms_atomic_commit_tail, instead of using the flip_done op, it used > wait_for_vblanks. Another way to prevent blocking was wait_one_vblank when > enabling crtc. However, in both cases, pipe-A-cursor-suspend persisted > blocking in the 2nd start of CRC capture, which may indicate that > something got stuck in the step of CRC setup. Indeed, wait_one_vblank in > the crc setup was able to sync things and free all kms_cursor_crc > subtests. Besides, other alternatives to force enabling vblanks or prevent > disabling them such as calling drm_crtc_put_vblank or modeset_enables > before commit_planes + offdelay = 0, also unlock all subtests executions. > > Finally, due to vkms's dependence on vblank interruptions to perform > tasks, this patch uses refcount to ensure that vblanks happen when > enabling composer and while crc capture is needed. > > Cc: Rodrigo Siqueira > Cc: Haneen Mohammed > > Co-debugged-by: Sidong Yang > Signed-off-by: Sidong Yang > Signed-off-by: Melissa Wen > Reviewed-by: Daniel Vetter > > --- > > v2: > - extract a vkms_set_composer helper > - fix vblank refcounting for the disabling case > > v3: > - make the vkms_set_composer helper static > - review the credit tags Thanks a lot for your work here, patch merged to drm-misc-next. I've kept the changelog in the commit message, I often find that quite useful. But that's a bit a drm peculiarity, most other subsystems prefer it like you've done it. Cheers, Daniel > > --- > drivers/gpu/drm/vkms/vkms_composer.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c > index b8b060354667..4f3b07a32b60 100644 > --- a/drivers/gpu/drm/vkms/vkms_composer.c > +++ b/drivers/gpu/drm/vkms/vkms_composer.c > @@ -233,6 +233,22 @@ int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name, > return 0; > } > > +static void vkms_set_composer(struct vkms_output *out, bool enabled) > +{ > + bool old_enabled; > + > + if (enabled) > + drm_crtc_vblank_get(&out->crtc); > + > + spin_lock_irq(&out->lock); > + old_enabled = out->composer_enabled; > + out->composer_enabled = enabled; > + spin_unlock_irq(&out->lock); > + > + if (old_enabled) > + drm_crtc_vblank_put(&out->crtc); > +} > + > int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name) > { > struct vkms_output *out = drm_crtc_to_vkms_output(crtc); > @@ -241,9 +257,7 @@ int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name) > > ret = vkms_crc_parse_source(src_name, &enabled); > > - spin_lock_irq(&out->lock); > - out->composer_enabled = enabled; > - spin_unlock_irq(&out->lock); > + vkms_set_composer(out, enabled); > > return ret; > } > -- > 2.27.0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch