drivers: usb: xhci: set HID bit in streaming endpoint contexts #6461
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The xHC may commence Host Initiated Data Moves for streaming endpoints -
see USB3.2 spec s8.12.1.4.2.4. However, this behaviour is typically
counterproductive as the submission of UAS URBs in {Status, Data,
Command} order and 1 outstanding IO per stream ID means the device never
enters Move Data after a HIMD for Status or Data stages with the same
stream ID. For OUT transfers this is especially inefficient as the host
will start transmitting multiple bulk packets as a burst, all of which
get NAKed by the device - wasting bandwidth.
Also, some buggy UAS adapters don't properly handle the EP flow control
state this creates - e.g. RTL9210.
Set Host Initiated Data Move Disable to always defer stream selection to
the device. xHC implementations may treat this field as "don't care,
forced to 1" anyway - xHCI 1.2 s4.12.1.
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
|
Tested and this fixes my issue, LGTM! |
popcornmix
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kernel: drivers: usb: xhci: set HID bit in streaming endpoint contexts See: raspberrypi/linux#6461
popcornmix
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to raspberrypi/firmware
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Nov 11, 2024
kernel: drivers: usb: xhci: set HID bit in streaming endpoint contexts See: raspberrypi/linux#6461
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This fixes @naushir's reboot IO errors and also stops shallow IO depths from getting spurious NAKed packets.
The rationale in the commit message applies globally, which is why this isn't an RP1-specific quirk. I believe the VL805 implements this field as ignored-1.