On Tue, 15 Nov 2011, Geoff Levand wrote:
> PS3 EHCI HC errata fix 236 - During high speed bulk out and high speed control
> out transfers the PS3 EHCI HC will issue an OUT token on the USB bus when a
> device responds with a NAK. The USB 2.0 standard specifies that a PING token
> must be output. The work-around is for the HC driver to initialize the
> RL (NAK count reload) field of the queue head to a non-zero value.
This can't be right. The RL field is already initialized to
EHCI_TUNE_RL_HS, which is #defined as 4.
Maybe for PS3 EHCI you want to #define it as 2 instead.
> Signed-off-by: Geoff Levand <geoff@xxxxxxxxxxxxx>
> ---
> drivers/usb/host/ehci-hcd.c | 1 +
> drivers/usb/host/ehci-q.c | 1 +
> 2 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index 3ff9f82..e43cb5a 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -620,6 +620,7 @@ static int ehci_init(struct usb_hcd *hcd)
> hw = ehci->async->hw;
> hw->hw_next = QH_NEXT(ehci, ehci->async->qh_dma);
> hw->hw_info1 = cpu_to_hc32(ehci, QH_HEAD);
> + hw->hw_info1 |= cpu_to_hc32(ehci, (2 << 28)); /* RL = 2 */
Unnecessary; the ring-head QH is never used for any transfers.
> hw->hw_token = cpu_to_hc32(ehci, QTD_STS_HALT);
> hw->hw_qtd_next = EHCI_LIST_END(ehci);
> ehci->async->qh_state = QH_STATE_LINKED;
> diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
> index 4e4066c..7794c7a 100644
> --- a/drivers/usb/host/ehci-q.c
> +++ b/drivers/usb/host/ehci-q.c
> @@ -911,6 +911,7 @@ qh_make (
>
> case USB_SPEED_HIGH: /* no TT involved */
> info1 |= (2 << 12); /* EPS "high" */
> + info1 |= (2 << 28); /* RL = 2 */
> if (type == PIPE_CONTROL) {
> info1 |= (EHCI_TUNE_RL_HS << 28);
The line you just added isn't needed, because of this line here.
Furthermore, RL isn't used with interrupt transfers, and setting it to
a nonzero value in an interrupt QH might not be safe.
Alan Stern
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