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 76B6AE68149 for ; Tue, 17 Feb 2026 08:59:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 36A6210E499; Tue, 17 Feb 2026 08:59:47 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="g7M0o7p8"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id 263BD10E499; Tue, 17 Feb 2026 08:59:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1771318785; x=1802854785; h=date:from:to:cc:subject:message-id:reply-to:references: in-reply-to:mime-version; bh=pd9S/8jFxd5YP9Metn2nmyxnL+pX1wGXScbpbuXooHg=; b=g7M0o7p8s4AmPLT05pER+qolDbkEQC0CRXD51MM7o3OFQZw1bB6PSqvo EYROhHKoMRQBQjuM5EAbjaKnok+lm0fcXQKgLhTpwUFXJ+oz5QiR+gIfd jH7rKsnjyzwMOxHUMY/vSKA6jKSJ16h0Yv1RjS5dT9Bg+QeuXXFJzcfjF cwwu0qQFHt9RERGqQa/8ykrN493Cmk02+LsO+OV/QLyO30qODTRnPQpjP nmKPpw3sT2d5Qp59uPunPb8IMsP2nmJdatIq1NiU/MCm9JKzfKPYphroB OR7os1DMeD/21Mmb+PAPJNRVOHgswem/gWljmi/sqtUI8aZKDgRyJ1eZ4 g==; X-CSE-ConnectionGUID: b8Zb53kNTEyksufPNjBJOg== X-CSE-MsgGUID: IZfz+h5KQFqs8BJhhECMrQ== X-IronPort-AV: E=McAfee;i="6800,10657,11703"; a="76224087" X-IronPort-AV: E=Sophos;i="6.21,295,1763452800"; d="scan'208";a="76224087" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2026 00:59:44 -0800 X-CSE-ConnectionGUID: GQxoO+WJRdKAPtWlAxQzEA== X-CSE-MsgGUID: dIHRF5oJSQ6ZHtFhDFSi2g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,295,1763452800"; d="scan'208";a="217782203" Received: from orsmsx902.amr.corp.intel.com ([10.22.229.24]) by fmviesa004.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2026 00:59:44 -0800 Received: from ORSMSX903.amr.corp.intel.com (10.22.229.25) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.35; Tue, 17 Feb 2026 00:59:43 -0800 Received: from ORSEDG902.ED.cps.intel.com (10.7.248.12) by ORSMSX903.amr.corp.intel.com (10.22.229.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.35 via Frontend Transport; Tue, 17 Feb 2026 00:59:43 -0800 Received: from SN4PR2101CU001.outbound.protection.outlook.com (40.93.195.20) by edgegateway.intel.com (134.134.137.112) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.35; Tue, 17 Feb 2026 00:59:43 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=JJT0A3w530aVZ9bnQ1Qc6JASi2BpPxJN+KEKnEPY1NLuZBALgENi37H710SlSPxvd6dxIdLo59dP3PLX/vkTBbtn3z50V99hRtrtqM8lqirGQCCsULVsEFrDDWher189kT4L4LkZIhq3WNzRAunbs9t+qunY5gzA4YFfHDjIFNw/V8rks+3+0P+g2wTSWlk72wdYL0BxFN53yLSxgkqkiyQCntOdQ2CYXkbylpTeOUQLMk82SNd8ZNBrD5svuybZZtmknRjpXX2dahgpmNO0MlM2YjbryXFDyJymorX+IVk/z2BuabRxukb05cmIbzMuxpxEDV7ORcre9NDCrQxMjA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=BYYO/c3CNHmPzPFmRoCTxMmdH//6tlTIBIWcu4rm9Yg=; b=K+JkHXP0Clb3zm2uLOGFJMCb0Q9OKRAHLiiwexSzeP4gL3rsAhMBr3P+nJKgUtzytTWMdeAMeEgxco7vZAsHFFsWE1r4wmrWLcZpzTj/FXSZmk1d0e0CYq4y2SpujQMb4kly+T8TdV3EGIOQ0HwDoC0AO80jtR/T0OZR73zvXRgOg7S6vL5b87qAe8CU1rVGfdSLldQ52j8REn4QeyE8KR9Yei9OKTV0Jay6MDW7F/+BMr8W1WiEyxLqOcRX3RpKr+ZJusubG1gC2E+teL+lXYWZ+6+eBrTZmec4U1XdfJWLAH7YEudy1HZJrpRwncw9Rx9HRyssQO2WC/2onehs7g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from SJ0PR11MB4845.namprd11.prod.outlook.com (2603:10b6:a03:2d1::10) by CH3PR11MB7390.namprd11.prod.outlook.com (2603:10b6:610:14e::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9632.13; Tue, 17 Feb 2026 08:59:41 +0000 Received: from SJ0PR11MB4845.namprd11.prod.outlook.com ([fe80::9ca5:4d1d:db45:f523]) by SJ0PR11MB4845.namprd11.prod.outlook.com ([fe80::9ca5:4d1d:db45:f523%5]) with mapi id 15.20.9611.013; Tue, 17 Feb 2026 08:59:41 +0000 Date: Tue, 17 Feb 2026 10:59:16 +0200 From: Imre Deak To: Ankit K Nautiyal CC: , Subject: Re: [PATCH 4/4] drm/i915/dp_mst: Allow modes requiring compression for DSC passthrough Message-ID: References: <20260216070421.714884-1-imre.deak@intel.com> <20260216070421.714884-5-imre.deak@intel.com> <9961da24-68c6-4633-846e-7b059b45858c@intel.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <9961da24-68c6-4633-846e-7b059b45858c@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland X-ClientProxiedBy: GV3PEPF00002BC0.SWEP280.PROD.OUTLOOK.COM (2603:10a6:144:1:0:6:0:11) To SJ0PR11MB4845.namprd11.prod.outlook.com (2603:10b6:a03:2d1::10) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ0PR11MB4845:EE_|CH3PR11MB7390:EE_ X-MS-Office365-Filtering-Correlation-Id: 6cd85443-3a1b-4703-4155-08de6e02e28d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?8LZq33OX/f8C8L9gjfi8RAyhLMqwG5ECYF2Tv/dZg0REfjPmMkJAOPfoAErP?= =?us-ascii?Q?eEPjpclAvweHeE3ZaJUdj+Mozwt9EXjn836ltmUUv0Klj0iV3Pfn8uNf9d7T?= =?us-ascii?Q?Y5Vk/eLxyib76Uik0oTkEQAvqZ0ifCNJgUiQb4JXnE8bvAlfc0+34bk6lwrR?= =?us-ascii?Q?CHr4+TwiwDkrTMWPv4gwX6hTpwyPD/efu9Rc63an/tRrzJe5SWwx4KbJUiwZ?= =?us-ascii?Q?LQL4cy7jsjFieyrp0cvkP9ikI7XrPpDlmFbg7EJKo0mQhJa7uDKlZrBpx4a6?= =?us-ascii?Q?YHFUl7Wtzm/isUKsoGZ5Fc4IEi7FqBJoqmsrX1/OH3KJweUZzmXtz6bfTjSB?= =?us-ascii?Q?KxJPsPkgtHTf0Okzr8ZNh5kGsN/PWNU5JJLgADgmV1K/Kx9cxWsVh6PempZN?= =?us-ascii?Q?pm1g5X0Yut78ARaCVg7S5+zPZnm0JIJ+ZX4hVjVTNPG9llFsktaUComObQbC?= =?us-ascii?Q?bH79pmp0YM27dZ14jQ8z75nu5bj1UcxKpFZ9TZ8HEEoNmb3UwErrZAAYeIVH?= =?us-ascii?Q?5aodnpBZ469xSrqnS/vlYN+TyVPc9/4VmateL/NRljgj+vgMweV9HRtfi7bH?= =?us-ascii?Q?JEOIGH/mBbViUu2GAObwDVDpkN66YMx/qjNWhs4shc9HNeNxABty2AiLSQ99?= =?us-ascii?Q?XpcvMFn6ohRwUYkbimO6oDmZPDGd6+8R4Ab8WlxeKj5jZoW14MnVSWpEoix4?= =?us-ascii?Q?kRLdta+IJ0LzDWOWeC+UkaXW5sVp+uikhAnhUf280HV1zHNqLrwKiz335IGh?= =?us-ascii?Q?eM7tgpN+1MbRS6J9sYVXS9GCFVQmNDAzLY5XhnDcdO3Pu0pRY/YQlJ1dgrbu?= =?us-ascii?Q?88S8X62JIzPwAessPtgEyrNGW+8TziaJj4j6O88skjuXucyIXx4hUOptmiKP?= =?us-ascii?Q?J/e/koQ8JF+dGRlCCfgAPTHXj0nCK4iIVGwufqZJm976N8NUJrgf+sBnb29S?= =?us-ascii?Q?+vbJ0HceeuPd+3F36aimvqj0d7g9A+m/i0LWO66+cS9n7etLYArkdps+rQuv?= =?us-ascii?Q?h5JYLIOHwYdSHwg2EfXQ2FRetPDSgOJqkjLxXSnlH8nwbgYrMEnev11dErDm?= =?us-ascii?Q?mTafsAypUYy/ewQw4TRI4Y/OhmTVTdwBs3t/1rz+Us5pvQAJq5/AtrgjATpu?= =?us-ascii?Q?6X2EDjWTlUik3g3U48uYEs+GkofTwQ7S0+kL05a9AQTkIvPxdvyKauGJ3Nj4?= =?us-ascii?Q?nHQLO9UvjRdm+8fpAWV3/+scYBcAs1RZ/EdOHY6V6It8EeEpOZ5ydhXnC6Yy?= =?us-ascii?Q?yRJ8e+GWB5xmnZq7tiqqaYm9/V+iVZxe2/4TCyWQOqvdjrVALcQ57/e7Qqfu?= =?us-ascii?Q?ixzL7T3uOew08upUI8HFS9XZkcactCM4nwgElhqGQqa0O85Xdqw/EUSMudcM?= =?us-ascii?Q?2NBwJCqQKevFR+zg+iBLZ43OFZatGJWTRpl+whBwycRSZqe1ze6SWSOOj+lV?= =?us-ascii?Q?wXjhuR8vdVhlPE4tiDqpxWAINsYw+aPniT8X9nGtq07CLwxwSbeyGvhoA2GO?= =?us-ascii?Q?pUZ5IG81npUySv6ywwGqIx7w4R6wGMD4ToyM?= X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:SJ0PR11MB4845.namprd11.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230040)(1800799024)(376014)(366016); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?UqvlsxPyT3Ke7cGQeuMk6Xzue2/NWSfWDEIpTvln+GnaJeCkn8aEC+4a09HJ?= =?us-ascii?Q?/1fnIZLRE0x0pOV6Q9C0HL1gEqKyon7OAD/fHDkwdk+C7O8pf9asYOqA7Z3v?= =?us-ascii?Q?gSqQ8J1hrzAr1RdFkFg6f50HRnILWWiBRhpvxVwzLSpJ7DCZqi+T1UNK1U6K?= =?us-ascii?Q?VDTTfNjnf/RRasUol+UBdACDZ9UqNW6ht/V67REjis/KoHdCx5ufDwoOQd0I?= =?us-ascii?Q?6dIpMCN5/6uj3irQTI/xfM7DWKkfq+ZYV506QmwYTXNKtCrNbmzSuWznxWHm?= =?us-ascii?Q?jzAjlGdMxuDDd0SnTKi3tbqAz1oq5HzjHWelrcwQ+zq4AULNtvKnzZgdWGTM?= =?us-ascii?Q?mLpiI9ajjFp7x0/DhsuZ2V5I538LXYhP//qVTZVfzlHW496U/CLdZJkuEiSp?= =?us-ascii?Q?ozzxcYhqi/su76um8XRS+YNhDwRHlQFM35ADtPy+pwGeptVHeXIZHQ4D1xu1?= =?us-ascii?Q?OmQkIVSEi40kzUzAYlUGQzEVvBej/Nwc2gsm3e7KYGO/Lh1Mmri20T6BhMZT?= =?us-ascii?Q?1JpGMiP488jsRKDRoYMowH2ZwUKRNzXg6rJBiUFTLJsZVcN3zBGH7GWOxYs9?= =?us-ascii?Q?KuTOI4Cv6SV2Kf0BuO0Gme/oKEjJ2tmDTOsBU4Chz4q3BAIFwMtqbk5hWAKa?= =?us-ascii?Q?eq2VnIv8QKUg1NCO7OzKG4im699N57S8KiZfDpofPY058T4L4dzWGpxEFam1?= =?us-ascii?Q?q/+qNh4k0OSSQ4yoDh02fRIT9FZixAX32nUfLkpQ9O3ScLW81oworF+GVogz?= =?us-ascii?Q?khrEwifE431o0fCkPvBaIy2VMRW5of07SRgt6fN/bjkWd5HXlg0DbpCn6Z/1?= =?us-ascii?Q?CPQInZ5wp1bszmlwBFH+TLAt6bLLj+UN6P4hwNyCKLHVlJNDGs06x2nGMwt6?= =?us-ascii?Q?kq/tK2d2VtlXRes5FbNgUhoTECal3zDfwcwvfPui0tjqWOXZU2og+dzEjtcd?= =?us-ascii?Q?2QeZbXI//Er4YoVBeTNS9rTtCjxJluYn7VqQZvxz/9y9yxrizJwkoiIoZA94?= =?us-ascii?Q?47LoTYLUy/xUaAvN0oVIztBcVdWVNbBw+uuhtaLdkTvFhsSb83onTy9CFBeT?= =?us-ascii?Q?Q8w/OOMxsqv+t4D2/wwKnXzQDGA0ZPdlcixve4x86LKv3eH8W7s3SGtsd4ws?= =?us-ascii?Q?/H59t6vgafNsEBPqQ35fDW3mJlOatKd14xNn7h6vWEcQca+Hz1AnkZg2PQzf?= =?us-ascii?Q?RfDK9DJLv3qilCsZa7DDgX/Q1uwKyUGdhenVfEWqHED2b2ycTC3zSYzaiE1s?= =?us-ascii?Q?alXVCjA1paHa2W6pKQ4VNw7B2ZnRfeOSrS6T1O11QNZKG6PW7sDxrErQ7L1c?= =?us-ascii?Q?K5kcD+qK2Emdudv6nFPnAY2gh3iUOHm2hk/KNrlltLuKVtZ8cV/u2K/NlTiF?= =?us-ascii?Q?faSh/Jtgf0nw6ebWS0VUt30KK+dS1MCwY5irUbBHhQhetLPmF2FmlYaSOUHO?= =?us-ascii?Q?xds+YtCLVGHxuykTGds94pl0zDUSBiurtiAMQW1UTW5KzK5XB4ljpoKbKmL6?= =?us-ascii?Q?lssviDtfcqZ+EknbXhONm7Hs3zzcLkOyJminaWuIpWmxBBcfYeHrdQaCXmCW?= =?us-ascii?Q?DqZMjfjIjoGzJBluXP7+y1fDkVzeSMz1LAYi58ARE/ZMe26kPqlAceOSdb7P?= =?us-ascii?Q?Q8GHTnciPmYK0yXdQ5RXWglEL0N2ZFf1S0YlOH48pK1ymFtIf/CB69+7HP8t?= =?us-ascii?Q?tAR2kHGF+K9+dXDgi/7zbnfxod5WxASdFSfClv0qww+uwdJoeGBJ7O25VoyI?= =?us-ascii?Q?6Xpxhotxug=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 6cd85443-3a1b-4703-4155-08de6e02e28d X-MS-Exchange-CrossTenant-AuthSource: SJ0PR11MB4845.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Feb 2026 08:59:41.5190 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: PAvxYwsiYA0+crO9kZ+5HLfOn0k/Rg80zlINDHGI9sHkTOtCelQ4j56hdECUpW+za4KZlgD8bXGRWTh2KFRtVw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR11MB7390 X-OriginatorOrg: intel.com X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: imre.deak@intel.com Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, Feb 17, 2026 at 10:23:51AM +0530, Ankit K Nautiyal wrote: > > On 2/16/2026 12:34 PM, Imre Deak wrote: > > The DSC passthrough mode allows a compressed stream to be forwarded > > to the sink instead of being decompressed at the last MST branch > > device, provided that the branch device supports passthrough and > > the sink supports decompression. This enables modes that would not > > be possible without compression, as the bandwidth required for the > > uncompressed stream exceeds what is available on the full MST path > > from source to sink. > > > > Currently, MST mode validation assumes the stream is uncompressed > > and uses the corresponding uncompressed minimum link BPP for > > bandwidth calculation. Use the minimum compressed link BPP instead > > when DSC passthrough is available to enable the modes described > > above. > > > > The non-passthrough DSC mode, where the last MST branch device > > decompresses the stream, may also allow enabling additional modes. > > This would require determining the link bandwidth between the last > > branch device and the sink based on the > > DFP_Link_Available_Payload_Bandwidth_Number reported by the branch > > device for the sink via the ENUM_PATH_RESOURCES MST message. > > Supporting this is left for a follow-up for the following reasons: > > > > 1. DFP Link Available PBN reporting is not supported by any of the > > available MST devices used for testing. > > 2. Non-passthrough mode would enable additional modes only if the link > > bandwidth between the last branch device and the sink exceeded that > > of the full MST path. Unless multiple MST devices are used, or link > > training forces a reduced bandwidth between the source and the first > > branch device, both rare cases, this is unlikely. > > > > Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4332 > > Signed-off-by: Imre Deak > > > Makes sense to leave the non-passthrough mode for follow up. > > Perhaps our kms_linktrain_fallback can be tweaked to test DSC > non-passthrough and passthrough modes. Yes, it's a good idea to test whether, with a reduced link rate / lane count, modes that did not need compression with the original link configuration continue to be enumerated/enabled correctly when switching to DSC. I don't think this should be part of the LT fallback test; it could instead be a separate DSC test by just forcing a lower link rate / lane count there. > Not directly related but perhaps still on the topic: currently we are not > exposing dsc related debugfs for MST connectors. > > With the recent changes and checks for intel_dp->force_dsc_en in place for > MST, can we start exposing the dsc related debugfs' for MST too? MST connectors, and in general the whole DSC debugfs interface, need some changes. Adding a way to control the passthrough / non-passthrough mode (probably just a disable_passthrough connector debugfs entry) should be added as well. I have some changes for this and plan to follow up with them. > (Though, there are still things which cannot be tested on MST - BPC tests, > output format etc.) > > In any case the changes look good to me. > > Reviewed-by: Ankit Nautiyal Regards, > > Ankit > > > --- > > drivers/gpu/drm/i915/display/intel_dp_mst.c | 18 ++++++++++++++++-- > > 1 file changed, 16 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c > > index 7ca2e2245fc70..f833f47643271 100644 > > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c > > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c > > @@ -1467,6 +1467,7 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector, > > unsigned long bw_overhead_flags = > > DRM_DP_BW_OVERHEAD_MST | DRM_DP_BW_OVERHEAD_SSC_REF_CLK; > > int min_link_bpp_x16 = fxp_q4_from_int(18); > > + static bool supports_dsc; > > int ret; > > bool dsc = false; > > int target_clock = mode->clock; > > @@ -1491,6 +1492,13 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector, > > return 0; > > } > > + supports_dsc = intel_dp_has_dsc(connector) && > > + drm_dp_sink_supports_fec(connector->dp.fec_capability); > > + > > + if (supports_dsc && connector->mst.port->passthrough_aux) > > + min_link_bpp_x16 = intel_dp_compute_min_compressed_bpp_x16(connector, > > + INTEL_OUTPUT_FORMAT_RGB); > > + > > max_link_clock = intel_dp_max_link_rate(intel_dp); > > max_lanes = intel_dp_max_lane_count(intel_dp); > > @@ -1504,6 +1512,13 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector, > > /* > > * TODO: > > * - Also check if compression would allow for the mode > > + * in non-passthrough mode, i.e. the last branch device > > + * decompressing the stream. This makes a difference only if > > + * the BW on the link between the last branch device and the > > + * sink is higher than the BW on the whole MST path from the > > + * source to the last branch device. Relying on the extra BW > > + * this provides also requires the > > + * DFP_Link_Available_Payload_Bandwidth_Number described below. > > * - Calculate the overhead using drm_dp_bw_overhead() / > > * drm_dp_bw_channel_coding_efficiency(), similarly to the > > * compute config code, as drm_dp_calc_pbn_mode() doesn't > > @@ -1527,8 +1542,7 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector, > > for_each_joiner_candidate(connector, mode, num_joined_pipes) { > > int dsc_slice_count = 0; > > - if (intel_dp_has_dsc(connector) && > > - drm_dp_sink_supports_fec(connector->dp.fec_capability)) { > > + if (supports_dsc) { > > /* > > * TBD pass the connector BPC, > > * for now U8_MAX so that max BPC on that platform would be picked