From 9e47be0c97f7357b80e91dc0632e9cce2eb025e0 Mon Sep 17 00:00:00 2001 From: Bartlomiej Zolnierkiewicz Date: Sat, 26 Jan 2008 20:13:09 +0100 Subject: ide: remove broken disk byte-swapping support Remove broken disk byte-swapping support: - it can cause a data corruption on SMP (or if using PREEMPT on UP) - all data coming from disk are byte-swapped by taskfile_*_data() which results in incorrect identify data being reported by /proc/ide/ and IOCTLs - "hdx=bswap/byteswap" kernel parameter has been broken on m68k host drivers (including Atari/Q40 ones) since 2.5.x days (because of 'hwif' zero-ing) - byte-swapping is limited to PIO transfers (for working with TiVo disks on x86 machines using user-space solutions or dm-byteswap should result in much better performance because DMA can be used) For previous discussions please see: http://www.ussg.iu.edu/hypermail/linux/kernel/0201.0/0768.html http://lkml.org/lkml/2004/2/28/111 [ I have dm-byteswap device mapper target if somebody is interested (patch is for 2.6.4 though but I'll dust it off if needed). ] Acked-by: Sergei Shtylyov Signed-off-by: Bartlomiej Zolnierkiewicz --- Documentation/ide.txt | 4 ---- 1 file changed, 4 deletions(-) (limited to 'Documentation/ide.txt') diff --git a/Documentation/ide.txt b/Documentation/ide.txt index b29ccb43d6c..94e2e3b9e77 100644 --- a/Documentation/ide.txt +++ b/Documentation/ide.txt @@ -244,10 +244,6 @@ Summary of ide driver parameters for kernel command line "hdx=nodma" : disallow DMA - "hdx=swapdata" : when the drive is a disk, byte swap all data - - "hdx=bswap" : same as above.......... - "hdx=scsi" : the return of the ide-scsi flag, this is useful for allowing ide-floppy, ide-tape, and ide-cdrom|writers to use ide-scsi emulation on a device specific option. -- cgit v1.2.3-70-g09d2