Messages in this thread | | | Date | Wed, 26 Jan 2000 16:50:15 -0700 (MST) | Subject | Re: ide-scsi problems with multiple CD-Rs on same channel (2.2.14) | From | Tkil <> |
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>>>>> "Gadi" == Gadi Oxman <gadio@netvision.net.il> writes:
Gadi> I'd recommend changing choose_drive() in drivers/block/ide.c Gadi> as follows -- replacing the "drive = hwgroup->drive;" line with Gadi> "drive = hwgroup->drive->next;" line, and commenting out the Gadi> part later which tests the best->nice1 flag (the second part Gadi> of the patch can alternatively be done by using "echo nice1:0 > Gadi> /proc/ide/hdx/settings for each IDE drive).
Gadi> This will select round-robin scheduling between the drives. This Gadi> is usually not the best for throughput, but might be more Gadi> appropriate when real-time constrains are involved.
Well, a few issues:
1. Switching to hwgroup->drive->next causes serious problems at boot. The four IDE devices are detected, but it stops at the "partition check" for hda.
So I reverted this portion of the patch. It might still be usable, but I suspect that we would need to fix the termination condition there too.
2. I'm not sure if this patch fixed it or not, but I can now start a burn onto hdc, and the second burn onto hdb, successfully. Under the stock 2.2.14, I believe this caused problems, but I would have to run it again to make sure.
So, the short form is that I can get two burns (hdb and hdc) working flawlessly. Starting a third burn (so far just in -dummy mode) always hoses the second burn (assuming hdb, hdc, hdd order). I *can* read from all three devices simultaneously, as my previous e-mail indicated (with the exception of the "setup" period, which seems to block all other traffic off that bus). These drives do have 2MB buffers on them, so we should be able to take advantage of any burst traffic we can provide.
I will probably test 2.3.40 on this box pretty soon, and see if that gives us any better luck.
Thanks again, T.
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