Messages in this thread | | | Date | Wed, 26 Aug 2009 23:07:01 -0400 | From | Jeff Garzik <> | Subject | Re: ATA device reset, shoud I be concerned? |
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On 08/26/2009 10:40 PM, Robert Hancock wrote: > On 01/21/2008 08:33 AM, Tejun Heo wrote: >> Tejun Heo wrote: >>> IMHO, losing media error information is much better than locking up a >>> machine hard. We can start white listing known good controllers but I'm >>> skeptical how much benefit it will bring. >> >> Just a data point, even ICHs lock up after PHY event if the wrong TF >> register is accessed. I just don't think tempting with TF regs after >> timeout is worth the cost. > > Nvidia CK804 SATA controllers appear to also explode on reading TF > registers after media errors in certain cases. (They tend to either > lockup the machine or throw HyperTransport timeout machine check > exceptions). I suspect those error paths aren't well tested (except that > it even explodes in Windows with the default Microsoft IDE driver, when > reading a scratched DVD on a SATA drive, for example.)
Well, reading TF when DMA or other operation is enabled is a big no-no... according to spec. If we are touching TF before data xfer operation is completed, and host controller has a chance to receive D2H FIS, TF is undefined (except Status, in some cases).
Jeff
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