ATA Patch #6

[Matthew Dillon]

:Update: the lockup happens reading from an IDE drive with DMA enabled
:(no mater what speed it is). Writing to an IDE drive doesn't seem
:to have a problem. After I noticed this, I tried to reproduce the lockup
:with dd command to perform a repeated short reads from the disk:
:
:# dd if=/dev/ad0s1f of=/dev/null
:
:There's a short period of time before the box becomes unresponsive,
:during which pressing ctrl+T stops displaying the status(it eventually
:locks up no matter whether I press ctrl+T or not). I managed to press
:ctrl-alt-esc in the middle of(not sure if this is normal):

    Hmm.  This is very intriguing.  Can you perhaps get a kernel dump
    out of it?

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>

:lwkt_switch(c1610b00,56,c1619360,c1610b00,d1dd9a6c) at lwkt_switch+0x112
:mi_switch(c1610b00,c1610b00,3) at mi_switch+0xec
:tsleep(c18556a8,0,c02524c2,0) at tsleep+0x1da
:physio(c16e6788,d1dd9bdc,7f0000,d1dd9ae4,c16e6788) at physio+0x1ba
:disk_putport(d1e14090,d1dd9ae4) at disk_putport+0xb5
:lwkt_domsg(d1e14090,d1dd9ae4,0,0,0) at lwkt_domsg+0x1c
:dev_dread(c16e6788,d1dd9bdc,7f0000,d1dd9bdc,7f0000) at dev_dread+0x53
:svn_read(c16c3a00,d1dd9bdc,c17260f8,0,c1619360) at svn_read+0x103
:kern_readv(3,d1dd9bdc,0,d1dd9c50,8065000) at kern_readv+0xe6
:read(d1dd9c24,3,5d55f1,292,c02720e4) at read+0x69
:syscall2(806002f,2f,bfbf002f,bfbffd80,bfbffd90) at syscall2+0x230
:Xint0x80_syscall() at Xint0x80_syscall+0x2a