Gary Hade wrote:
Some of my random thoughts:
There does appear to be this invalid assumption that 0xFF status
always implies device-not-present. The status register access
restrictions in ATA/ATAPI-7 V1 5.14.2 include the statement "The
contents of this register, except for BSY, shall be ignored when
BSY is set to one." which the code does not honor. There is apparently
past experience that 0xFF status implies device-not-present for some
controllers (the odd clowns :) but I have no idea how common these are.
We obviously can't get rid of the check but since we cannot clear
the read-only status register and there appears to be no specification
dictated upper limit on how long it should take for a software reset to
complete it just seems like we need to wait long enough to support the
slowest known device which may be the GoVault.
SRST is specified to take no longer than 31 seconds from the clearing to
the SRST bit to the clearing of the BSY bit.
Look through the software reset protocol documentation (ATA/ATAPI-7
volume 2), mainly the device state machines.
Jeff
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