From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) (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 9D7451A0BD6 for ; Mon, 24 Feb 2025 15:38:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740411518; cv=none; b=Xa0Pmn6TbOVbgd/+mxEbmnKHHTFOKnYDsNDbfh3Wt77vb9G9GhgXuplyomB1PUtUh9XKQ0ifDASIWu2WeC80od+HKh78vAC+wcd+lCOEEYEhEXgWIL6pLhHlYQq4U+hsDttyDoS5LLczf3DXVhLY+JfDbgjFEWeGEGe4lMvI3Uc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740411518; c=relaxed/simple; bh=i6uCMpEqhNB6kv0LVixzotzNCRy5wG20H0n1NSAch2s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=N5tlFFVEjbJ/QzYbTPcO/TVtgLCqo81iqJZMC1UOPogOR5sZexNnruIBcYI1n9Tbf7g9sM1du77Mlmydv+yY2IRR+pupc/V7YXZQN9V3ziQ3qzoWVYxSD24NN1YSj33coIL4AsrEMQUHZ/ChSOW37YOKfrSXeJB4mY1xcabacP8= 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=XOaK6H1O; arc=none smtp.client-ip=192.198.163.16 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="XOaK6H1O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1740411516; x=1771947516; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=i6uCMpEqhNB6kv0LVixzotzNCRy5wG20H0n1NSAch2s=; b=XOaK6H1OwqM3LF9ovM3iuQlg20doUfekQMPjcxHg0YNsj5s9+dmjKoTQ 5MJOiGDajvUfiAYm9tOpVIqG6ks+oWOTGq4lFLN2bcrxxIPbWxQ/DSTeW akeHTAlYnNr7Nfc1fu2qGY49SRHSmj3EYvEush6cMtX+4umBbQdIQINy5 7C3beQbh8nmwmWTeaxZ+gcVAIoyIZKrssS/GKOfO/rJftGNCEicCVscvY 0NZ7Lw6ckDqnEhTcvD+fuKHREIVPl7IXPgkAPLeE5OtonnLagAyzkTYqP dNES02mO6RO8sAKfbGWRrTKc2fvC2i5+u9e6+/MI/pY9xfjVR3Gz4EHqW A==; X-CSE-ConnectionGUID: p7kyNRK8QruDyRWC18dobw== X-CSE-MsgGUID: 3YqwupBbSw6g9gbn80yDNg== X-IronPort-AV: E=McAfee;i="6700,10204,11355"; a="28768079" X-IronPort-AV: E=Sophos;i="6.13,309,1732608000"; d="scan'208";a="28768079" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2025 07:38:35 -0800 X-CSE-ConnectionGUID: Urim1mgrS46kj6kdqihpLA== X-CSE-MsgGUID: DsOQ8Y36Rtu7vYIkDpoV3A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.13,309,1732608000"; d="scan'208";a="121057026" Received: from smile.fi.intel.com ([10.237.72.58]) by orviesa004.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2025 07:38:32 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1tmaXN-0000000EjYk-2LcO; Mon, 24 Feb 2025 17:38:29 +0200 Date: Mon, 24 Feb 2025 17:38:29 +0200 From: "andriy.shevchenko@linux.intel.com" To: Aditya Garg Cc: "maarten.lankhorst@linux.intel.com" , "mripard@kernel.org" , "tzimmermann@suse.de" , "airlied@gmail.com" , "simona@ffwll.ch" , Kerem Karabay , Atharva Tiwari , Aun-Ali Zaidi , Linux Kernel Mailing List , "dri-devel@lists.freedesktop.org" Subject: Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs Message-ID: References: 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: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote: > > On 24 Feb 2025, at 8:50 PM, Aditya Garg wrote: > >> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote: > >> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote: > >>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote: > >>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote: > >>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote: > >>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote: ... > >>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3])) > >>>>>>> > >>>>>>> As commented previously this is quite strange what's going on with endianess in > >>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being > >>>>>>> open coded and force-cast to __le32. > >>>>>> > >>>>>> I would assume it was also mimicked from the Windows driver, though I haven't > >>>>>> really tried exploring this there. > >>>>>> > >>>>>> I’d rather be happy if you give me code change suggestions and let me review > >>>>>> and test them > >>>>> > >>>>> For the starter I would do the following for all related constants and > >>>>> drop that weird and ugly macros at the top (it also has an issue with > >>>>> the str4 length as it is 5 bytes long, not 4, btw): > >>>>> > >>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */ > >>> > >>> Lemme test this. > >> > >> Just in case it won't work, reverse bytes in the integer. Because I was lost in > >> this conversion. > > > > It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same. > > And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc > in reverse order, probably the reason %p4ch was chosen. And I am unable to > find what macro upstream can be used. %.4s should work as it technically not DRM 4cc, but specifics of the protocol (that reminds me about ACPI that uses 4cc a lot). -- With Best Regards, Andy Shevchenko