#17275: [USB] Stack drivers do not properly handle non-isolated fragmented
transfers
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Reporter: waddlesplash | Owner: waddlesplash
Type: bug | Status: assigned
Priority: normal | Milestone: Unscheduled
Component: Drivers/USB | Version: R1/beta3
Keywords: | Blocked By:
Blocking: | Platform: All
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In hrev55441, I implemented support for fragmented transfers in XHCI.
However, upon further reflection, there is a critical problem here: if
more than just the one fragmented transfer is queued at once, then all but
the first part of the fragmented transfer will be inadvertently
"interspersed" with parts of other transfers, which will cause data
corruption, etc. among other problems.
Looking at EHCI and other stack drivers, it appears they all have this
exact same oversight. I guess nothing that uses fragmented transfers
queues multiple things at once, or else it already would have run into
this issue.
Possibly the right thing to do in this case is just to return an error
code. I'm not quite sure what the right one would be. Maybe
{{{B_DEV_RESOURCE_CONFLICT}}}? Or just {{{B_BUSY}}}? "Too many requests"
would be the real error code, but we do not have one for that.
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Ticket URL: <https://dev.haiku-os.org/ticket/17275>
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