On Sun, 16 Mar 2008 12:39:43 -0700 (PDT)..
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
On Sun, 16 Mar 2008, Alan Cox wrote:No it doesn't. DRQ simply means "drive has more data for the controllerA _lot_ of chips require you to clear the DRQ by taking the data they have.
if you want it". Interrupts are controlled via IEN and the interrupt line.
Almost none and mostly very old ones. I'm not saying we shouldn't do it
(except where it hangs the hardware - hence the FIFO flag) but for the
traces presented and hardware reported it appears to be a bit of a red
herring.
If the drive wants to give us data and we end the transaction that isMore than a few tiny devices from what I remember. It tends to be the other way around - most devices do *not* want to get new commands until you've finished the previous one by draining the queues.
fine. In practice a tiny few devices crap themselves if we don't.
Not in my experience having maintained a lot of ATA drivers for a very
long time. In fact the changes for draining the DRQ went into libata only
very recently because it was only when we had a distro sized userbase
with PATA devices that it became apparent that a few corner case problems
remained.