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Commit b0391523 authored by Jonathan Bell's avatar Jonathan Bell Committed by Dom Cobley
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usb: xhci: expand mitigations for VLI_SS_BULK_OUT_BUG quirk



The VL805 can cause data corruption if a SS Bulk OUT endpoint enters a
flow-control condition and there are TRBs in the transfer ring that are
not an integral size of wMaxPacket and the endpoint is behind one or more
hubs.

This is frequently the case encountered when FAT32 filesystems are
present on mass-storage devices with cluster sizes of 1 sector, and the
filesystem is being written to with an aggregate of small files.

The initial implementation of this quirk separated TRBs that didn't
adhere to this limitation into two - the first a multiple of wMaxPacket
and the second the 512-byte remainder - in an attempt to force TD
fragments to align with packet boundaries. This reduced the incidence
rate of data corruption but did not resolve it.

The fix as recommended by VIA is to disable bursts if this sequence of
TRBs can occur.

Limit turning off bursts to just USB mass-storage devices by searching
the device's configuration for an interface with a class type of
USB_CLASS_MASS_STORAGE.

Signed-off-by: default avatarJonathan Bell <jonathan@raspberrypi.com>
parent 00353b29
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