From mboxrd@z Thu Jan 1 00:00:00 1970 From: Albert ARIBAUD Date: Tue, 31 Aug 2010 07:38:24 +0200 Subject: [U-Boot] [PATCH] display_buffer: fix misaligned buffer In-Reply-To: References: <1282940584-27957-1-git-send-email-u-boot@emk-elektronik.de> <4C7B7864.2080607@emk-elektronik.de> <4C7B7C52.1040606@emk-elektronik.de> <4C7B889B.305@denx.de> <4C7BB41F.7030003@emk-elektronik.de> <4C7BF271.1050808@free.fr> Message-ID: <4C7C9550.2010703@free.fr> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Le 31/08/2010 00:29, Detlev Zundel a ?crit : > Hi Albert, > >> Le 30/08/2010 18:47, Detlev Zundel a ?crit : >>> Hi Reinhard, >>> >>>> Detlev Zundel schrieb: >>>> >>>>>> Detlev, regarding the discussion I would only point out that we have to >>>>>> be sure that such kind of patch will be merged in the current release. >>>>>> It would be a real pity if a new official realease is published and then >>>>>> even a simple "md" command does not work on ARM. >>>>> >>>>> I don't see a problem here. All proposed patches (with/without >>>>> attribute and union) surely fix a bug, so they will go into mainline >>>>> when consent is reached on which one to use. This should well happen >>>>> before the pending release on September 12th[1]. >>>>> >>>>> Am I misunderstanding anything here? >>>> >>>> No... but I would require that the "union" approach would be wanted, >>>> BEFORE I put effort into doing it. >>> >>> I'd very much appreciate your effort as I want the solution now that you >>> did whet my appetite. >> >> Besides, re: 'fixing with the side-effect of a different thing': I think >> the alignment caused by using an union is not actually a side effect of >> it but an intended effect of it, as the compiler must ensure correct >> alignment of each union member -- on architectures where alignment of >> 32-bit ints is unnecessary, the union will not cause undue alignment, >> whereas the __aligned__ attribute would. > > Absolutely and that's why I like the solution. It clearly states the > intentions of the code. > > The 'side effect of another thing' that I was talking about was the > proposed local change of using an uint32_t array for something which > originally was an uint8_t array in order to gain the alignment. I apologize, then. I did not understand your post this way because I was considering the uint32_t in the union, which is 'legitimate' as it is used for 'md.l'. Amicalement, -- Albert.