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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4B60BC433FE for ; Mon, 3 Oct 2022 11:11:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A7B1B89F1B; Mon, 3 Oct 2022 11:11:56 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 71B5089F1B for ; Mon, 3 Oct 2022 11:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1664795513; x=1696331513; h=from:to:subject:in-reply-to:references:date:message-id: mime-version:content-transfer-encoding; bh=ihsHxfxt+cTzsznNZq1rLhW7kw79fudpn7MmrWjr7kw=; b=SYG1Xpmn6KGp+Jbw2sNQ4zK4Q+bDGu7cDDJWlcaEZzHI/I7m3x+GjSCY WVg5edAJYydujl68KhOW/3UnqvsiYqSxxnLHAo0Bj4DUTpsYBY6Lrmz45 ED5c8isHXbeUF/BU81XtRXHhYArEpp0lfxNPA/DUzRNF49KBaCaSqS6jt FQVB1eyd/SzyuenC6VgPGFFIz2/eD932LkYkoZu2yaAwqEblTQOAh2x4H ha5n35Htc04PA0KQFhl/SbmFVfdu5axQY7FuEWOLea7Q+PP8NFq0XH414 Xk32hK+jrWd+5Gku06hmHhaTfxBwXlCbnJc/a8l0S/1UlC4mNm8cHZ5GY g==; X-IronPort-AV: E=McAfee;i="6500,9779,10488"; a="366649945" X-IronPort-AV: E=Sophos;i="5.93,365,1654585200"; d="scan'208";a="366649945" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2022 04:11:49 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10488"; a="618695727" X-IronPort-AV: E=Sophos;i="5.93,365,1654585200"; d="scan'208";a="618695727" Received: from zlukwins-mobl.ger.corp.intel.com (HELO localhost) ([10.252.60.249]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2022 04:11:47 -0700 From: Jani Nikula To: Ville Syrjala , intel-gfx@lists.freedesktop.org In-Reply-To: <20220927182455.3422-1-ville.syrjala@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20220927182455.3422-1-ville.syrjala@linux.intel.com> Date: Mon, 03 Oct 2022 14:11:44 +0300 Message-ID: <875yh1w49b.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Intel-gfx] [PATCH] drm/i915: Reject excessive dotclocks early 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, 27 Sep 2022, Ville Syrjala wrote: > From: Ville Syrj=C3=A4l=C3=A4 > > Make sure modes with crazy big dotclocks are rejected early, > so as to not cause problems for subsequent code via integer > overflows and whatnot. > > These would eventually be rejected in intel_crtc_compute_pipe_mode() > but that is now too late as we do the clock computations a bit > earlier than that. And we don't want to just reorder the two since > we still want to check the final computed dotclock against the > hardware limit to make sure we didn't end up above the limit due > to rounding/etc. > > Fixes: 0ff0e219d9b8 ("drm/i915: Compute clocks earlier") > Signed-off-by: Ville Syrj=C3=A4l=C3=A4 Too bad we can't really simplify and remove the check from connector mode valid hooks. Or we could but it gets tricky with the bigjoiner 2x stuff. Reviewed-by: Jani Nikula > --- > drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/d= rm/i915/display/intel_display.c > index eb8eaeb19881..04e8fa953bc7 100644 > --- a/drivers/gpu/drm/i915/display/intel_display.c > +++ b/drivers/gpu/drm/i915/display/intel_display.c > @@ -8130,6 +8130,17 @@ static void intel_setup_outputs(struct drm_i915_pr= ivate *dev_priv) > drm_helper_move_panel_connectors_to_head(&dev_priv->drm); > } >=20=20 > +static int max_dotclock(struct drm_i915_private *i915) > +{ > + int max_dotclock =3D i915->max_dotclk_freq; > + > + /* icl+ might use bigjoiner */ > + if (DISPLAY_VER(i915) >=3D 11) > + max_dotclock *=3D 2; > + > + return max_dotclock; > +} > + > static enum drm_mode_status > intel_mode_valid(struct drm_device *dev, > const struct drm_display_mode *mode) > @@ -8167,6 +8178,13 @@ intel_mode_valid(struct drm_device *dev, > DRM_MODE_FLAG_CLKDIV2)) > return MODE_BAD; >=20=20 > + /* > + * Reject clearly excessive dotclocks early to > + * avoid having to worry about huge integers later. > + */ > + if (mode->clock > max_dotclock(dev_priv)) > + return MODE_CLOCK_HIGH; > + > /* Transcoder timing limits */ > if (DISPLAY_VER(dev_priv) >=3D 11) { > hdisplay_max =3D 16384; --=20 Jani Nikula, Intel Open Source Graphics Center