Messages in this thread Patch in this message | | | Subject | Resend: PATCH: Stop 2.6.12rc rmmod from being able to destroy CD hardware | From | Alan Cox <> | Date | Fri, 27 May 2005 13:18:08 +0100 |
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On an rmmod the cdrom layer when used with ide-cd issues a cache flush atapi command to devices including those that do not support it. According to Jens earlier discussion this isn't merely a minor glitch but can destroy some CD hardware due to firmware bugs in the drive (as per the Mandrake incident)
The IDE CD layer uses a mask of unsupported features, this means that because ide-cd doesn't know about MRW writables it doesn't set the relevant bit for non writables and harm can occur.
The simple fix is attached, making the driver start from ~0 and mask bits the other direction would longer term be safer.
diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.12rc3/drivers/ide/ide-cd.c linux-2.6.12rc3-minoride/drivers/ide/ide-cd.c --- linux.vanilla-2.6.12rc3/drivers/ide/ide-cd.c 2005-04-27 16:01:29.000000000 +0100 +++ linux-2.6.12rc3-minoride/drivers/ide/ide-cd.c 2005-05-01 14:09:35.000000000 +0100 @@ -2860,6 +2922,9 @@ devinfo->mask |= CDC_CLOSE_TRAY; if (!CDROM_CONFIG_FLAGS(drive)->mo_drive) devinfo->mask |= CDC_MO_DRIVE; + + /* We must have this masked unless a drive definitely handles it */ + devinfo->mask |= CDC_MRW_W; devinfo->disk = info->disk; return register_cdrom(devinfo); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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