From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 41225606A337 for ; Tue, 27 Oct 2026 16:04:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=NDefxWy9 Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C55D010F6FE; Tue, 27 Oct 2026 16:04:49 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 29C6D10E443; Tue, 27 Oct 2026 16:04:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1793117084; x=1824653084; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=E17rDRpemwE0pwkgxrdTqZW6dJck+1yrSNqBwMignYw=; b=NDefxWy9XIdVWE0H+iKHQMr30/Sj6F2krIWPiKPIj1sgHXoPRdvsl6Ou T5IYuoXQNO2fgW8VjKhnjC1WWlbQH+8+o6UJm4oUw7DtOV3ZtRUdpqmyi vnV7p4P9t/TOoEgFASajAfDHqWb2HU1NnkVbjwMyuMbk2v+AmZD5fa2qC kBFVtdKJsgcNq7NDzsjiMOrlQCg2q7yM1MYu4+M70xr5U7CuRDGzIxDuR f9RkAhaVgqf1DGwFOmHIVcooeFIGuO1aIEFZVSAbVxqFUljQEKXqtibi1 Ou8VxmhxCUSms/GpCHe74WaC0tmXGw//z30oKDZ+QtW9/Lq1sqyWzTbSi Q==; X-CSE-ConnectionGUID: pBRIYXTARj+lXS6lYN7z8g== X-CSE-MsgGUID: mCySRIh8RLiTongJPvZ3FQ== X-IronPort-AV: E=McAfee;i="6800,10657,11948"; a="1830934" X-IronPort-AV: E=Sophos;i="6.27,181,1787036400"; d="scan'208";a="1830934" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Oct 2026 09:04:43 -0700 X-CSE-ConnectionGUID: f4gYiu7WQwevUfAeIPJcZw== X-CSE-MsgGUID: tDldDrB5QB+4CJE7egdoAQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,181,1787036400"; d="scan'208";a="4720089" Received: from ettammin-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.245.247]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Oct 2026 09:04:41 -0700 From: Jani Nikula To: Ville Syrjala , intel-gfx@lists.freedesktop.org Cc: intel-xe@lists.freedesktop.org Subject: Re: [PATCH 01/13] drm/i915/vrr: Fix intel_vrr_dcb_vmin_vblank_start() In-Reply-To: <20261023165803.31016-2-ville.syrjala@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland References: <20261023165803.31016-1-ville.syrjala@linux.intel.com> <20261023165803.31016-2-ville.syrjala@linux.intel.com> Date: Tue, 27 Oct 2026 18:04:39 +0200 Message-ID: <956f60a3c6194f7ab12f8cb44d413c0bb58ec541@intel.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Intel-gfx" X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Fri, 23 Oct 2026, Ville Syrjala wrote: > From: Ville Syrj=C3=A4l=C3=A4 > > intel_vrr_dcb_vmin_vblank_start() may evaluate > intel_vrr_dcb_vmin_vblank_start_next() twice, and given that > this is doing hardware access under the hood isn't really > desired. Feels like there's a word missing there. This? It? > Even worse, the double evaluation might even cause > intel_vrr_dcb_vmin_vblank_start() itself to finally > return -EINVAL (if we race against the DMC hard enough), > which we definitely never want to do. > > Eliminate the double evaluation, guaranteeing a sane > final return value at the same time. I think a Fixes: would be in order. Reviewed-by: Jani Nikula > > Signed-off-by: Ville Syrj=C3=A4l=C3=A4 > --- > drivers/gpu/drm/i915/display/intel_vrr.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i= 915/display/intel_vrr.c > index b14750692ae0..e59345bd1d33 100644 > --- a/drivers/gpu/drm/i915/display/intel_vrr.c > +++ b/drivers/gpu/drm/i915/display/intel_vrr.c > @@ -1202,9 +1202,13 @@ int intel_vrr_safe_window_start(const struct intel= _crtc_state *crtc_state) > static int > intel_vrr_dcb_vmin_vblank_start(const struct intel_crtc_state *crtc_stat= e) > { > - return (intel_vrr_dcb_vmin_vblank_start_next(crtc_state) < 0) ? > - intel_vrr_dcb_vmin_vblank_start_final(crtc_state) : > - intel_vrr_dcb_vmin_vblank_start_next(crtc_state); > + int vblank_start; > + > + vblank_start =3D intel_vrr_dcb_vmin_vblank_start_next(crtc_state); > + if (vblank_start < 0) > + vblank_start =3D intel_vrr_dcb_vmin_vblank_start_final(crtc_state); > + > + return vblank_start; > } >=20=20 > int intel_vrr_vmin_safe_window_end(const struct intel_crtc_state *crtc_s= tate) --=20 Jani Nikula, Intel