Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 15 Jan 2003 10:49:38 -0800 | From | Ross Biro <> | Subject | [BUG] 2.4.21-pre3 hdparm -X violates IDE locking |
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This bug impacts all versions of the kernel that I have looked at including 2.4.18 and above. It probably impacts many other versions as well.
hdparm -X issues a drive command ioctl which eventually issue a command to the drive bypassing all of the normal locking. The net effect is that a command can be set to the drive when the drive is not ready. Some drives lock up when this happens.
The call chain is
ide_ioctl calls ide_cmd_ioctl
If the command is a set features to change the communications speed, after the command is complete, ide_cmd_ioctl calls
ide_set_xfer_rate
ide_set_xfer_rate then calls drive->speedproc.
Most speedprocs then call ide_config_drive_speed ide_config_drive_speed issue a set features command. and busy waits on it.
The easiest fix is to probably modify execute_drive_command to update drive->current_speed when it issues the appropriate SET FEATURES command, and then have ide_config_drive_speed do nothing if speed == current_speed.
I did a much bigger modification that handles changing drive speed specially and immediately. I'll make patches for either one, but I wanted to get some opinions before I did so.
Ross
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