Re: "READ_BIG command timeout" on CDROM drive

From: <>
Date: Wed, 26 Mar 2003 16:22:09 EST
>> Hi all!
>> When I read cdroms with fbsd 5.0, the following message appears in the 
>> console very often (it seems to happen with every cdrom I try):
>>>acd0: READ_BIG command timeout - resetting
>>>ata0: resetting devices ..
>> It is repeated indefinitely and I can't kill -9 the process that is trying 
>> read the cdrom.
>> "umount -f /cdrom" also gets stuck and doesn't write any error messages.
>> The driver in use is cd9660: RockRidge Extension.
>> I have to reboot to have access to the cdrom drive again. And besides, the 
>> shutdown process does not end every time when the system is in this state.
>> Is there a means to have access to the cdrom drive again without rebooting?
>> I have not seen any bug report for this problem; am I right?
>Just wanted to report that I fixed this problem by adding:
>hw.ata.atapi_dma="1"    # Run the CD-ROM/DVD in DMA mode
>to /boot/loader.conf.  The system was trying to access the drive using 
>PIO4 rather than DMA and crapping out.  I got the idea from another 
>thread today with the subject "playing mp3's and burning a cd".  Just an 

Thanks for the tip, Scott.

I added the line to loader.conf, rebooted and verified the value with sysctl. 
After plenty of successful read accesses to cdroms, I was about to think it 
corrected the problem on my box too. But unfortunately, it occured again.
It does not happen as often as before; it seems it happens only with cdroms 
holding errors. But the symptoms and the solution (shutdown and reboot) 
remain the same :-(
Received on Wed Mar 26 2003 - 12:22:27 UTC

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