usb: xhci-mtk: add only one extra CS for FS/LS INTR
In USB2 Spec: "11.18.5 TT Response Generation In general, there will be two (or more) complete-split transactions scheduled for a periodic endpoint. However, for interrupt endpoints, the maximum size of the full-/low-speed transaction guarantees that it can never require more than two complete-split transactions. Two complete-split transactions are only required when the transaction spans a microframe boundary." Due to the maxp is 64, and less then 188 (at most in one microframe), seems never span boundary, so use only one CS for FS/LS interrupt transfer, this will save some bandwidth. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/5b9ff09f53d23cf9e5c5437db4ffc18b798bf60c.1615170625.git.chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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