Red Hat Bugzilla – Bug 55074
System hangs when mounting cdrom
Last modified: 2007-04-18 12:37:45 EDT
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Description of problem:
When trying to mount the CD-ROM immediately after installation, system
hangs. Doing the same thing, but using my CD-RW drive does not cause this
Version-Release number of selected component (if applicable):
Steps to Reproduce:
2. login as root on eg. tty1
3. toss a cd in the CD-ROM drive
4. mount /mnt/cdrom
Actual Results: for a couple of seconds mount just seemed to struggle
with spin-up etc. then it all hung completely(CD-ROM LED permanently on)
Expected Results: mount should return without any problem, letting me
access the contents of my CD in my CD-ROM drive
CD-ROM is on /dev/hdb, CD-RW is on /dev/hdc
Tried upgrading with all ERRATA as of Oct. 24th 2001(incl. new kernel),
Can you try "hdparm -d0 /dev/hdb" and then try to mount it ?
Some (well a LOT) of cdrom drives claim they can do IDE DMA, but just
hang the IDE bus when the operating system actually tries to use DMA.
running `hdparm -d0 /dev/hdb' before mounting the cd-rom actually solves the
problem. However I haven't had this problem before, on RHL71, is there any
chance it could have been caused by my moving the cdrom device from hdc(master)
to hdb(slave)... If you don't know the answer right off, don't spend any time
looking for an answer - I will try it myself.
What's the correct way of making the new non-DMA setting stick?
Making the hdparm stick is easiest done by adding the command to /etc/rc.local
Can you give me the output of
so that I can see if your cdrom drive is on the "don't do dma on these" list ?
Here is the output of /proc/ide/hdb/model:
The writer(hdc)'s model is this:
And then i noticet that during boot this is what is shown about the devices:
ide: Assuming 33MHz PCI bus speed for PIO modes; override with idebus=xx
PIIX4: IDE controller on PCI bus 00 dev 11
ide0: BM-DMA at 0xfff0-0xfff7, BIOS settings: hda:DMA, hdb:pio
ide1: BM-DMA at 0xfff8-0xffff, BIOS settings: hdc:pio, hdd:pio
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
ide1 at 0x170-0x177,0x376 on irq 15
Seems to me, that the devices are actually detected correctly, but that info
is not passed to the driver - or mayby I'm wrong!
Instead of doing a hdparm -d0 /dev/hdb, doing a hdparm -d1 -X34 /dev/hdb also
solves my problem...
It still puzzles me, however... I have never needed anything like this on any of
my previous Linux installations. I should probably mention, that I DID move my
IDE devices around when I was about to install RHL7.2.
I have experienced the same problem. My CD-ROM is a CRD-8400B too (on hdc),
while my writer is a Waitec Shuttle (on hdd). I have caused system hangs coth
when mount a cd as root and as a normal user. I have solved the problem with
'hdparm -d1 -X34 /dev/hdc'
I haven't moved my IDE devices before installing RHL7.2.
Well, I had the same problem, I solved in the same way, but before adding
a "hdparm ..." issue, I tried to mount a NON ISO9660 (HFS CDROM) FileSystem
thinking about a ISO9660-related bug... God! It worked fine!! So what about the
DMA NonDMA PIO mode problems, if I was able to mount the CD Disk WITHOUT
changing the hdparm... The funniest thing is during the installation process
with the same kernel (2.4.7-10BOOT vs 2.4.7-10) the system recognized the CD-
ROM Drive perfectly!!! What a hell?!?!?
Any explanation here??
I have a CRD-8400B on /dev/hda on an IBM NetFinity, and am having the same
problem also. No problems with previous Linux installs.
The BOOT kernel has dma disabled *hard*.
The drive is in the blacklist, but somehow this blacklist is getting ignored ;(
This problem has disappeared from me after updating the kernel to 2.4.9-XX. I'm
not sure which one. The 2.4.9-31 has not got this problem at my machine!
never saw this problem since - closing it - thanks for you help way back then :-)