From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (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 06ECC2571BD for ; Mon, 24 Feb 2025 15:36:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740411416; cv=none; b=N8Q5z9nVsL65wkVVLIf2vwdOxRopIeHBbX8TBjgaVsuQWY9lqzpxKOl6udQ/fPWARxz3tfNRErJA6nkh9x3SWU9F9SLph+HOUDJIRZqRqNQSiPO6ZY3PX7FeI132GpEzN0A3OToT0M6GIh0yiPzTgZFUAtnFlMKLVOkiPhFYUhk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740411416; c=relaxed/simple; bh=tlqeQlxXj7Z3p6b5lmb+YRd29W7Q03s6EkuRtxcr0LI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VSH73JQOoF0AJotNnDbkH3T4E/xEnquwuhQBZFDdpnKmhg/i7nNxrDqSlZi/57fvNssaQdMW9hV/b41w2FUp1TQWq/2xA1UnF+7TVe+VMzBwIdoGVLUwOWQiMnh6KlScOzrrpYB6W0OIrh4vdb9Pjz8Psz/0IbxZyppR8Mpm2LA= 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=SlzlIwEd; arc=none smtp.client-ip=198.175.65.18 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="SlzlIwEd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1740411415; x=1771947415; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=tlqeQlxXj7Z3p6b5lmb+YRd29W7Q03s6EkuRtxcr0LI=; b=SlzlIwEdeWgl7LT+hfWkr5sl7wQ0bEaEsAEMDCFQpW3BF7oyd6wTURoM mEOjDwO315rBnPilkllICQ81IVRHPsesvvFhdIv3ruY1l5bDTQ9dwZzqj Up5PGQg0H7nq9cDUtqnUnnpzEbj0Go7W2hKc5vDqvTJwrKSSetpPvdbTy 1MSPVzCv2kAXURUn4HKfzEJPQBtKB0A13/TEsEYhDu2KrToCVUILczTSc uNPfYcN7nlbRbqZCi1u7d7XmtwNBAtgE3Gx1QvpDKBUkBOAooaKP2db7Z dsY+PTpublSVe9S+TGm97RKPL8ZNeG0bQ/cDgdcxQqvdd8Za+jhbeYKiY A==; X-CSE-ConnectionGUID: Z5zHzrhPQb6YYeNOMdsI3A== X-CSE-MsgGUID: srNhmqOYRWuAHAnVQflSRA== X-IronPort-AV: E=McAfee;i="6700,10204,11314"; a="41379033" X-IronPort-AV: E=Sophos;i="6.12,310,1728975600"; d="scan'208";a="41379033" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2025 07:36:55 -0800 X-CSE-ConnectionGUID: EppH+i3LS6CwiRoOJoJ8Hg== X-CSE-MsgGUID: b5zUQ9CmTLu3d9WEAJr0bQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="120211657" Received: from smile.fi.intel.com ([10.237.72.58]) by fmviesa003.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2025 07:36:34 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1tmaVT-0000000EjWv-0igG; Mon, 24 Feb 2025 17:36:31 +0200 Date: Mon, 24 Feb 2025 17:36:30 +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 03:20:13PM +0000, 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. Right, the problem is the macro itself which does really weird things altogether. Using integer + comment much clearer in my opinion. > >>> (assuming we stick with __leXX for now). This will be much less confusing. -- With Best Regards, Andy Shevchenko