From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47ED11350D8 for ; Wed, 6 Mar 2024 15:06:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709737620; cv=none; b=dSXb4nfQa/q6KCJ5FFzS6C0jjqTRoZHhlW7EPVTKgoJJh+ssaDADYaWRksHRSgfxHUZmDc0dVZ1IdiUnGX+mVkqO5vUabr6UjFHYrWx5KT7N/ryDYfYesjQ02ZZ45M0S7Cn8ch+mFnbh2K/Ou185sEN0YMyakmqJMg7AzIFYT9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709737620; c=relaxed/simple; bh=NkW0kjqnGBo5wFggNC6XMC1hc0EuI58azaDi+ScyGKk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bOQchqCsfVMJDRWRGcOWjVhHMvfjW3t4VXnGWwBhOkG5miork0fWLPs7BulybhnZmnvaWRQLh+aIYr7Pl9zNLxQY8fiNA8M+PCE5Ar040t8qPcovXXkmXVy90U4z4dKSdkFsRfIaeWr2P4YT5oTAY0IA7EcKzse90cE+ugb/tg8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=le/G77he; arc=none smtp.client-ip=192.198.163.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="le/G77he" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1709737618; x=1741273618; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=NkW0kjqnGBo5wFggNC6XMC1hc0EuI58azaDi+ScyGKk=; b=le/G77heZ2Z+nHB46j4uQozOhKAorE/GbZq8ORyb11rUGIGFmeJfyqXk UqKk2EhjKZSRegqIDR9PbooQJXCS0xmCKH2qKqncX4KpvbxaAAXcKp6Y+ 4xmtGRYrp/yLRHmlh6o3SWhws3nkRSXXAu2G2O+1V/u3oIe5uiW089N6h ubHEJ0v5oxckU8ua1mDQ2FXgRGzQMMKFhfbzCKcJ+1KHP6+cPGoCq/0vp JijR+R7IlBtQOitwlpyn4l4k82zyhQkNayosJHLYQGmUWRECKWk+bbdt6 IoviZqnlG8n1i2qYdtQPM75N5MRuzotgPEOv/Zt9ehjd/xnWEBC6hc59K w==; X-IronPort-AV: E=McAfee;i="6600,9927,11004"; a="15008372" X-IronPort-AV: E=Sophos;i="6.06,208,1705392000"; d="scan'208";a="15008372" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2024 07:06:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,11004"; a="827774338" X-IronPort-AV: E=Sophos;i="6.06,208,1705392000"; d="scan'208";a="827774338" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.74]) by orsmga001.jf.intel.com with SMTP; 06 Mar 2024 07:06:52 -0800 Received: by stinkbox (sSMTP sendmail emulation); Wed, 06 Mar 2024 17:06:51 +0200 Date: Wed, 6 Mar 2024 17:06:51 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Rob Clark Cc: Thomas Zimmermann , Douglas Anderson , dri-devel@lists.freedesktop.org, Rob Clark , Javier Martinez Canillas , Daniel Vetter , Dave Airlie , David Airlie , Maarten Lankhorst , Maxime Ripard , =?iso-8859-1?Q?Ma=EDra?= Canal , Sean Paul , linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/udl: Add ARGB8888 as a format Message-ID: References: <20240227141928.1.I24ac8d51544e4624b7e9d438d95880c4283e611b@changeid> <60dc7697-d7a0-4bf4-a22e-32f1bbb792c2@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Patchwork-Hint: comment On Wed, Mar 06, 2024 at 06:49:15AM -0800, Rob Clark wrote: > On Wed, Mar 6, 2024 at 4:18 AM Thomas Zimmermann wrote: > > > > Hi, > > > > sorry that I did not see the patch before. > > > > Am 27.02.24 um 23:19 schrieb Douglas Anderson: > > > Even though the UDL driver converts to RGB565 internally (see > > > pixel32_to_be16() in udl_transfer.c), it advertises XRGB8888 for > > > compatibility. Let's add ARGB8888 to that list. > > > > We had a heated discussion about the emulation of color formats. It was > > decided that XRGB8888 is the only format to support; and that's only > > because legacy userspace sometimes expects it. Adding other formats to > > the list should not be done easily. > > OTOH it is fixing a kernel change that broke userspace > > > > > > > This makes UDL devices work on ChromeOS again after commit > > > c91acda3a380 ("drm/gem: Check for valid formats"). Prior to that > > > commit things were "working" because we'd silently treat the ARGB8888 > > > that ChromeOS wanted as XRGB8888. > > > > This problem has been caused by userspace. Why can it not be fixed there? > > > > And udl is just one driver. Any other driver without ARGB8888, such as > > simpledrm or ofdrm, would be affected. Do these work? > > Probably any driver where ARGB8888 is equivalent to XRGB8888 (ie. > single primary plane, etc) should advertise both. To me that seemes likely to trick userspace developers into assuming that ARGB is always available, and then when they finally try on hardware that doesn't have ARGB it'll just fail miserably. -- Ville Syrjälä Intel