From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- drivers/char/ftape/README.PCI | 81 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 drivers/char/ftape/README.PCI (limited to 'drivers/char/ftape/README.PCI') diff --git a/drivers/char/ftape/README.PCI b/drivers/char/ftape/README.PCI new file mode 100644 index 00000000000..18de159d36e --- /dev/null +++ b/drivers/char/ftape/README.PCI @@ -0,0 +1,81 @@ +Some notes for ftape users with PCI motherboards: +================================================= + +The problem: +------------ + +There have been some problem reports from people using PCI-bus based +systems getting overrun errors. +I wasn't able to reproduce these until I ran ftape on a Intel Plato +(Premiere PCI II) motherboard with bios version 1.00.08AX1. +It turned out that if GAT (Guaranteed Access Timing) is enabled (?) +ftape gets a lot of overrun errors. +The problem disappears when disabling GAT in the bios. +Note that Intel removed this setting (permanently disabled) from the +1.00.10AX1 bios ! + +It looks like that if GAT is enabled there are often large periods +(greater than 120 us !??) on the ISA bus that the DMA controller cannot +service the floppy disk controller. +I cannot imagine this being acceptable in a decent PCI implementation. +Maybe this is a `feature' of the chipset. I can only speculate why +Intel choose to remove the option from the latest Bios... + +The lesson of this all is that there may be other motherboard +implementations having the same of similar problems. +If you experience a lot of overrun errors during a backup to tape, +see if there is some setting in the Bios that may influence the +bus timing. + +I judge this a hardware problem and not a limitation of ftape ;-) +My DOS backup software seems to be suffering from the same problems +and even refuses to run at 1 Mbps ! +Ftape will reduce the data-rate from 1 Mbps to 500 Kbps if the number +of overrun errors on a track exceeds a threshold. + + +Possible solutions: +------------------- + +Some of the problems were solved by upgrading the (flash) bios. +Other suggest that it has to do with the FDC being on the PCI +bus, but that is not the case with the Intel Premiere II boards. +[If upgrading the bios doesn't solve the problem you could try +a floppy disk controller on the isa-bus]. + +Here is a list of systems and recommended BIOS settings: + + + Intel Premiere PCI (Revenge): + +Bios version 1.00.09.AF2 is reported to work. + + + + Intel Premiere PCI II (Plato): + +Bios version 1.00.10.AX1 and version 11 beta are ok. +If using version 1.00.08.AX1, GAT must be disabled ! + + + + ASUS PCI/I-SP3G: + +Preferred settings: ISA-GAT-mode : disabled + DMA-linebuffer-mode : standard + ISA-masterbuffer-mode : standard + + + DELL Dimension XPS P90 + +Bios version A2 is reported to be broken, while bios version A5 works. +You can get a flash bios upgrade from http://www.dell.com + + +To see if you're having the GAT problem, try making a backup +under DOS. If it's very slow and often repositions you're +probably having this problem. + + --//-- + LocalWords: ftape PCI bios GAT ISA DMA chipset Mbps Kbps FDC isa AF ok ASUS + LocalWords: SP linebuffer masterbuffer XPS http www com -- cgit v1.2.3