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 B5C5DC02182 for ; Tue, 21 Jan 2025 14:38:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5F05910E5D7; Tue, 21 Jan 2025 14:38:29 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="OaAwLm39"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) by gabe.freedesktop.org (Postfix) with ESMTPS id B6EE010E5D7 for ; Tue, 21 Jan 2025 14:38:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1737470308; x=1769006308; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=HzVo9yPpsqhp1crzChWM0Pprz+MbUDRA16WBkOYQ1q4=; b=OaAwLm397+JMzZ9zwtCWNVKJNX8iaZQ9PtqXoMLkts/jtX4lCBTZvihg C1hGsvK2dqV/2P+zJqu1Jds1+/rrae1CRK64WIQLaHUEu0/dIedFlwA1Z cZ361+du0nSJ3ubrOXjkgjEodKMbo+bU1+zO0jpIcxkfNSQ2oOojYClxj 25ts4jOGmUK+BTVEHKv5EWXdWPaUs649LHu/2VM3ndVWueJnQBL+3YT2U vYPGDcXrGXSwV4CKrT7fURmcITQZQCuPTxa1SxdAb18f/FYwOkVURTcdz Ls8auQfh7a1wwi6OoneE0zfqDrAjRL4QhcjL16le25HUmXH+w0iEMc+yN Q==; X-CSE-ConnectionGUID: 7v26Vj1pQu2dD/0y+0kdyA== X-CSE-MsgGUID: JAnpL+ntT824UQEsKv2DUQ== X-IronPort-AV: E=McAfee;i="6700,10204,11322"; a="38037122" X-IronPort-AV: E=Sophos;i="6.13,222,1732608000"; d="scan'208";a="38037122" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jan 2025 06:38:27 -0800 X-CSE-ConnectionGUID: TNeEfjboRt6R6jQQJanMLg== X-CSE-MsgGUID: MddVg7TOTiuVZkY111AqFA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.13,222,1732608000"; d="scan'208";a="106939151" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.74]) by fmviesa008.fm.intel.com with SMTP; 21 Jan 2025 06:38:25 -0800 Received: by stinkbox (sSMTP sendmail emulation); Tue, 21 Jan 2025 16:38:23 +0200 Date: Tue, 21 Jan 2025 16:38:23 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Jani Nikula Cc: intel-gfx@lists.freedesktop.org, Paz Zcharya Subject: Re: [PATCH 1/8] drm/i915: Keep TRANS_VBLANK.vblank_start==0 on ADL+ even when doing LRR updates Message-ID: References: <20250116201637.22486-1-ville.syrjala@linux.intel.com> <20250116201637.22486-2-ville.syrjala@linux.intel.com> <875xm9qvmo.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <875xm9qvmo.fsf@intel.com> X-Patchwork-Hint: comment 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 Mon, Jan 20, 2025 at 06:48:31PM +0200, Jani Nikula wrote: > On Thu, 16 Jan 2025, Ville Syrjala wrote: > > From: Ville Syrjälä > > > > intel_set_transcoder_timings() will set TRANS_VBLANK.vblank_start to 0 > > for clarity on ADL+ (non-DSI) because the hardware no longer uses that > > value. So the same in intel_set_transcoder_timings_lrr() to make sure > > the registers stay constitent even when doing LRR timing updates. > > > > Cc: Paz Zcharya > > Signed-off-by: Ville Syrjälä > > Hmm, so how come this doesn't warrant a change in readout? > > Apparently because intel_get_transcoder_timings() overwrites the read > value for display 13+ and non-dsi. Hrmh. Yeah, it's a bit dodgy. I did originally ponder about adding some kind of sanity check to readout too, but the GOP might still put something into TRANS_VBLANK.vblank_start which would cause a false positive. > > Reviewed-by: Jani Nikula > > > > --- > > drivers/gpu/drm/i915/display/intel_display.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c > > index f5d2eacce119..5ba3b2d658e5 100644 > > --- a/drivers/gpu/drm/i915/display/intel_display.c > > +++ b/drivers/gpu/drm/i915/display/intel_display.c > > @@ -2923,6 +2923,14 @@ static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc > > crtc_vblank_start = adjusted_mode->crtc_vblank_start; > > crtc_vblank_end = adjusted_mode->crtc_vblank_end; > > > > + if (DISPLAY_VER(dev_priv) >= 13) { > > + /* > > + * VBLANK_START not used by hw, just clear it > > + * to make it stand out in register dumps. > > + */ > > + crtc_vblank_start = 1; > > + } > > + > > drm_WARN_ON(&dev_priv->drm, adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE); > > > > /* > > -- > Jani Nikula, Intel -- Ville Syrjälä Intel