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SubjectRe: [PATCH] usb: dwc3: core: Disable USB2.0 phy suspend when dwc3 acts as host role
Date

Hi,

Baolin Wang <baolin.wang@linaro.org> writes:
> When dwc3 controller acts as host role with attaching slow speed device
> (like mouse or keypad). Then if we plugged out the slow speed device,
> it will timeout to run the deconfiguration endpoint command to drop the
> endpoint's resources. Some xHCI command timeout log as below when
> disconnecting one slow device:
>
> [ 99.807739] c0 xhci-hcd.0.auto: Port Status Change Event for port 1
> [ 99.814699] c0 xhci-hcd.0.auto: resume root hub
> [ 99.819992] c0 xhci-hcd.0.auto: handle_port_status: starting port
> polling.
> [ 99.827808] c0 xhci-hcd.0.auto: get port status, actual port 0 status
> = 0x202a0
> [ 99.835903] c0 xhci-hcd.0.auto: Get port status returned 0x10100
> [ 99.850052] c0 xhci-hcd.0.auto: clear port connect change, actual
> port 0 status = 0x2a0
> [ 99.859313] c0 xhci-hcd.0.auto: Cancel URB ffffffc01ed6cd00, dev 1,
> ep 0x81, starting at offset 0xc406d210
> [ 99.869645] c0 xhci-hcd.0.auto: // Ding dong!
> [ 99.874776] c0 xhci-hcd.0.auto: Stopped on Transfer TRB
> [ 99.880713] c0 xhci-hcd.0.auto: Removing canceled TD starting at
> 0xc406d210 (dma).
> [ 99.889012] c0 xhci-hcd.0.auto: Finding endpoint context
> [ 99.895069] c0 xhci-hcd.0.auto: Cycle state = 0x1
> [ 99.900519] c0 xhci-hcd.0.auto: New dequeue segment =
> ffffffc1112f0880 (virtual)
> [ 99.908655] c0 xhci-hcd.0.auto: New dequeue pointer = 0xc406d220 (DMA)
> [ 99.915927] c0 xhci-hcd.0.auto: Set TR Deq Ptr cmd, new deq seg =
> ffffffc1112f0880 (0xc406d000 dma),
> new deq ptr = ffffff8002175220
> (0xc406d220 dma), new cycle = 1
> [ 99.931242] c0 xhci-hcd.0.auto: // Ding dong!
> [ 99.936360] c0 xhci-hcd.0.auto: Successful Set TR Deq Ptr cmd,
> deq = @c406d220
> [ 99.944458] c0 xhci-hcd.0.auto: xhci_hub_status_data: stopping port
> polling.
> [ 100.047619] c0 xhci-hcd.0.auto: xhci_drop_endpoint called for udev
> ffffffc01ae08800
> [ 100.057002] c0 xhci-hcd.0.auto: drop ep 0x81, slot id 1, new drop
> flags = 0x8, new add flags = 0x0
> [ 100.067878] c0 xhci-hcd.0.auto: xhci_check_bandwidth called for udev
> ffffffc01ae08800
> [ 100.076868] c0 xhci-hcd.0.auto: New Input Control Context:
>
> ......
>
> [ 100.427252] c0 xhci-hcd.0.auto: // Ding dong!
> [ 105.430728] c0 xhci-hcd.0.auto: Command timeout
> [ 105.436029] c0 xhci-hcd.0.auto: Abort command ring
> [ 113.558223] c0 xhci-hcd.0.auto: Command completion event does not match
> command
> [ 113.569778] c0 xhci-hcd.0.auto: Timeout while waiting for configure
> endpoint command
>
> The reason is it will suspend USB phy to disable phy clock when
> disconnecting the slow USB decice, that will hang on the xHCI commands
> executing which depends on the phy clock.
>
> Thus we should disable USB2.0 phy suspend feature when dwc3 acts as host
> role.
>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
> drivers/usb/dwc3/core.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 9a4a5e4..0b646cf 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -565,6 +565,20 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
> if (dwc->revision > DWC3_REVISION_194A)
> reg |= DWC3_GUSB2PHYCFG_SUSPHY;
>
> + /*
> + * When dwc3 controller acts as host role with attaching one slow speed
> + * device (like mouse or keypad). Then if we plugged out the slow speed
> + * device, it will timeout to run the deconfiguration endpoint command.
> + * The reason is it will suspend USB phy to disable phy clock when
> + * disconnecting slow speed decice, which will affect the xHCI commands
> + * executing.
> + *
> + * Thus we should disable USB 2.0 phy suspend feature when dwc3 acts as
> + * host role.
> + */
> + if (dwc->dr_mode == USB_DR_MODE_HOST || dwc->dr_mode == USB_DR_MODE_OTG)
> + reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;

which version of the core you're using? Recent version (since 1.94A,
IIRC) can manage core suspend automatically. Also, this patch of yours
will cause a power consumption regression.

--
balbi
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