On Wed, 17 Aug 2011, River Wang wrote:
> From: Wang Zhi <zhi.wang@xxxxxxxxxxxxx>
> Date: Wed, 17 Aug 2011 03:35:43 -0700
> Subject: [PATCH]: USB: Enable IO watchdog for Intel MPH core to
> resolve USB stick reconnecting issue.
>
> On Intel Oaktrail platform, the USBSTS.USBINT interrupt may come too
> early before data is really ready especially when USB mass storage
> device is doing busy IO transactions: USBINT comes, but
> ehci_work()->scan_async() doesn't complete any urb from QHs. This will
> cause USB reconnecting issue on some SanDisk and SSK card reader.So we
> enable IO watchdog to kick this.
>
> Here is the log:
>
> [ 95.454965] scan_async() - 1262: Scan. qh: 0xf4ad2448.
> [ 95.455018] ehci_hcd 0000:0c:16.0: submit_async 1.4.4 urb f479f5e8
> ep1in len 122880, qtd f4b6a060 [qh f53da2e8]
> [ 95.460048] scan_async() - 1262: Scan. qh: 0xf4ad2448.
> [ 95.460063] start_unlink_async() - 1246: S CMD_IAAD, qh: 0xf4ad2448.
>
> /* Interrupt comes too early. */
> [ 95.460131] ehci_hcd 0000:0c:16.0: irq status 7c0a9 PPCE Async
> Periodic IAA FLR INT
> [ 95.460141] end_unlink_async() - 1187: qh: 0xf4ad2448.
>
> /* but scan_async doesn't complete any urb, so we really HANG here.*/
> [ 95.460148] scan_async() - 1262: Scan. qh: 0xf53da2e8.
>
> /* ehci_dbg_timer() is used to monitor registers when interrupt doesn't come. */
> [ 96.912107] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
> [ 98.904196] ehci_dbg_timer() - 146: USBCMD: 0x00018035, USBSTS: 0x0007c088.
> [ 98.916117] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
> [ 100.908183] ehci_dbg_timer() - 146: USBCMD: 0x00018035, USBSTS: 0x0007c088.
> [ 100.920114] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
> [ 102.912182] ehci_dbg_timer() - 146: USBCMD: 0x00018035, USBSTS: 0x0007c088.
> [ 102.924114] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
> [ 104.916150] ehci_dbg_timer() - 146: USBCMD: 0x00018035, USBSTS: 0x0007c088.
> [ 104.928110] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
> [ 106.920167] ehci_dbg_timer() - 146: USBCMD: 0x00018035, USBSTS: 0x0007c088.
> [ 106.932112] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
> [ 108.924161] ehci_dbg_timer() - 146: USBCMD: 0x00018035, USBSTS: 0x0007e088.
> [ 108.936113] ehci_dbg_timer() - 146: USBCMD: 0x00018005, USBSTS: 0x00000088.
>
> /* I type a key on my USB keyboard. Interrupt comes again. 2 urb is
> completed. We are alive again.*/
> [ 109.279368] ehci_hcd 0000:0c:16.0: irq status 7c089 PPCE Async
> Periodic FLR INT
>
> [ 109.279393] scan_async() - 1262: Scan. qh: 0xf53da2e8.
>
> /* This is the urb comes late. */
> [ 109.279423] ehci_hcd 0000:0c:16.0: ehci_urb_done 1.4.4 urb f479f5e8
> ep1in status 0 len 122880/122880
>
> [ 109.279499] scan_async() - 1262: Scan. qh: 0xf53da2e8.
>
> /* This is the interrupt urb from keyboard. */
> [ 109.279534] ehci_hcd 0000:0c:16.0: ehci_urb_done 1.4.1 urb f46924b8
> ep1in status 0 len 8/8
>
> Signed-off-by: Wang Zhi <zhi.wang@xxxxxxxxxxxxx>
> ---
> ehci-pci.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> index 1102ce6..a96b13c 100644
> --- a/drivers/usb/host/ehci-pci.c
> +++ b/drivers/usb/host/ehci-pci.c
> @@ -139,6 +139,20 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
> || pdev->device == 0x0829) {
> ehci_info(ehci, "disable lpm for langwell/penwell\n");
> ehci->has_lpm = 0;
> +
> + /* On Intel Oaktrail platform, the USBSTS.USBINT
> + * interrupt may come too early before data is
> + * ready especially when USB mass storage device
> + * is doing busy IO transactions: USBINT comes,
> + * but ehci_work()->scan_async() doesn't complete
> + * any urb from QHs. This will cause USB reconnecting
> + * issue on some SanDisk stick and SSK card reader.
> + *
> + * So we enable IO watchdog to kick this. */
> +
> + ehci_info(ehci, "enable IO watchdog for "
> + "langwell/penwell\n");
> + ehci->need_io_watchdog = 1;
> }
> if (pdev->device == PCI_DEVICE_ID_INTEL_CE4100_USB) {
> hcd->has_tt = 1;
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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