From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "Michel Dänzer" <michel@daenzer.net>
Cc: paulus@samba.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, Ian Munsie <imunsie@au1.ibm.com>
Subject: Re: Introduce support for little endian PowerPC
Date: Tue, 05 Oct 2010 09:50:32 +1100 [thread overview]
Message-ID: <1286232632.2463.324.camel@pasglop> (raw)
In-Reply-To: <1286188242.15020.349.camel@thor.local>
On Mon, 2010-10-04 at 12:30 +0200, Michel Dänzer wrote:
> > And last I looked X still pukes if you give it a pixmap in non native
> > byte order but that might have been fixed.
>
> I'm not sure what exactly you mean by that, but I'm not aware of any
> such issues offhand.
Hrm, I meant on the DDX side. Anyways, doesn't matter. Even if it works
fine on X side. Fact is, there's tons and tons of existing SW stack and
drivers on the field that are totally incapable of doing BE and
essentially unfixable without major work that the customer(s) is(are)
unwilling to do at this stage.
(Think embedded gfx IP cores mostly, including codecs etc...)
> I didn't say anything about that, just that IME it should be mostly
> possible to deal with endianness within the driver stack.
To some extent yes. Completely, I'm not sure. Apps manipulating pixels,
such as video players doing hand-made overlay etc... will potentially
have issues. It's more than actual pixel byte ordering. It's anything
that accesses a quantity in memory using different size accessors, ie,
storing a u32 and then expecting to find the LSB at u8* of the same
address etc... that sort of stuff happens more often in gfx-oriented
code than anywhere else in my experience.
> Note that I'm not arguing against these changes, just pointing out some
> apparent inaccuracies in the reasoning for them.
Right, I possibly made an incorrect statement relative to Xorg (I had
assumed the fb layer only worked properly in native endian format), but
that doesn't matter much since the problem here is existing code &
drivers and goes way beyond X (probably no X on the target setups
anyways).
Cheers,
Ben
next prev parent reply other threads:[~2010-10-04 22:50 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-01 7:05 Introduce support for little endian PowerPC Ian Munsie
2010-10-01 7:05 ` [PATCH 01/18] powerpc: Add ability to build little endian kernels Ian Munsie
2010-10-01 9:18 ` Kumar Gala
2010-10-01 11:28 ` Josh Boyer
2010-10-01 12:09 ` Benjamin Herrenschmidt
2010-10-01 11:40 ` Josh Boyer
2010-10-01 12:22 ` Benjamin Herrenschmidt
2010-10-01 7:05 ` [PATCH 02/18] powerpc: Add CROSSBE_COMPILE to build big endian boot wrapper Ian Munsie
2010-10-01 7:13 ` Geert Uytterhoeven
2010-10-01 7:19 ` Ian Munsie
2010-10-01 7:05 ` [PATCH 03/18] powerpc: Support parsing a little endian kernel from zImage wrapper Ian Munsie
2010-10-01 7:05 ` [PATCH 04/18] powerpc: Allow taishan platform to boot a little endian kernel Ian Munsie
2010-10-01 7:05 ` [PATCH 05/18] powerpc: Wire up 44x little endian boot for remaining 44x targets Ian Munsie
2010-10-01 11:27 ` Josh Boyer
2010-10-06 1:28 ` Ian Munsie
2010-10-06 1:55 ` Josh Boyer
2010-10-06 2:10 ` Sean MacLennan
2010-10-01 7:05 ` [PATCH 06/18] powerpc 44x: Set E bit in TLBs and PTEs when CPU is in little endian mode Ian Munsie
2010-10-01 7:06 ` [PATCH 07/18] powerpc: Use generic bitops for little endian bitmap operations Ian Munsie
2010-10-01 7:06 ` [PATCH 08/18] powerpc: Include the appropriate endianness header Ian Munsie
2010-10-01 7:06 ` [PATCH 09/18] powerpc: Support device tree regardless of CPU endianness Ian Munsie
2010-10-03 3:15 ` Grant Likely
2010-10-03 6:22 ` Benjamin Herrenschmidt
2010-10-01 7:06 ` [PATCH 10/18] powerpc: Support endian agnostic MMIO Ian Munsie
2010-10-01 7:06 ` [PATCH 11/18] powerpc: Make assembly endian agnostic when accessing 64bit values Ian Munsie
2010-10-01 7:06 ` [PATCH 12/18] powerpc 44x: Handle TLB miss regardless of endianness Ian Munsie
2010-10-01 7:06 ` [PATCH 13/18] powerpc 44x: Make DCR endianness agnostic Ian Munsie
2010-10-01 7:06 ` [PATCH 14/18] powerpc, of_serial: Endianness issues setting up the serial ports Ian Munsie
2010-10-07 23:23 ` Grant Likely
2010-10-01 7:06 ` [PATCH 15/18] mtd: Fix endianness issues from device tree Ian Munsie
2010-10-01 19:29 ` Artem Bityutskiy
2010-10-01 7:06 ` [PATCH 16/18] powerpc: Fix endianness issues in alignment handler Ian Munsie
2010-10-01 7:06 ` [PATCH 17/18] net: Fix endianess issues in IBM newemac driver Ian Munsie
2010-10-01 7:06 ` [PATCH 18/18] powerpc: Fix jiffies variable on little endian Ian Munsie
2010-10-01 9:02 ` Introduce support for little endian PowerPC Kumar Gala
2010-10-01 11:30 ` Josh Boyer
2010-10-01 11:55 ` Gary Thomas
2010-10-01 12:15 ` Benjamin Herrenschmidt
2010-10-01 12:37 ` Gary Thomas
2010-10-01 12:14 ` Benjamin Herrenschmidt
2010-10-01 16:20 ` Michel Dänzer
2010-10-01 20:50 ` Benjamin Herrenschmidt
2010-10-04 10:30 ` Michel Dänzer
2010-10-04 22:50 ` Benjamin Herrenschmidt [this message]
2010-10-01 17:59 ` Kumar Gala
2010-10-01 20:51 ` Benjamin Herrenschmidt
2010-10-01 22:03 ` Olof Johansson
2010-10-01 22:28 ` Benjamin Herrenschmidt
2010-10-07 16:25 ` Hollis Blanchard
2010-10-01 11:36 ` Josh Boyer
2010-10-01 12:21 ` Benjamin Herrenschmidt
2010-10-06 1:04 ` Ian Munsie
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