On Mon, 20 Mar 2017, Gerd Hoffmann wrote:
> On a loaded virtualization host (dozen guests booting at the same time)
> it may happen that the ohci controller emulation doesn't manage to do
> timely frame processing, with the result that the io watchdog fires and
> considers the controller being dead, even though it's only the emulation
> being unusual slow due to the load peak.
>
> So, add a quirk for qemu and don't use the watchdog in case we figure we
> are running on emulated ohci. The virtual ohci controller masquerades
> as apple ohci controller, but we can identify it by subsystem id.
>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> ---
> drivers/usb/host/ohci-hcd.c | 3 ++-
> drivers/usb/host/ohci-pci.c | 16 ++++++++++++++++
> drivers/usb/host/ohci.h | 1 +
> 3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
> index b6daf2e..5f81a2b 100644
> --- a/drivers/usb/host/ohci-hcd.c
> +++ b/drivers/usb/host/ohci-hcd.c
> @@ -231,7 +231,8 @@ static int ohci_urb_enqueue (
>
> /* Start up the I/O watchdog timer, if it's not running */
> if (!timer_pending(&ohci->io_watchdog) &&
> - list_empty(&ohci->eds_in_use)) {
> + list_empty(&ohci->eds_in_use) &&
> + !(ohci->flags & OHCI_QUIRK_QEMU)) {
> ohci->prev_frame_no = ohci_frame_no(ohci);
> mod_timer(&ohci->io_watchdog,
> jiffies + IO_WATCHDOG_DELAY);
> diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c
> index bb15096..a84aebe 100644
> --- a/drivers/usb/host/ohci-pci.c
> +++ b/drivers/usb/host/ohci-pci.c
> @@ -164,6 +164,15 @@ static int ohci_quirk_amd700(struct usb_hcd *hcd)
> return 0;
> }
>
> +static int ohci_quirk_qemu(struct usb_hcd *hcd)
> +{
> + struct ohci_hcd *ohci = hcd_to_ohci(hcd);
> +
> + ohci->flags |= OHCI_QUIRK_QEMU;
> + ohci_dbg(ohci, "enabled qemu quirk\n");
> + return 0;
> +}
> +
> /* List of quirks for OHCI */
> static const struct pci_device_id ohci_pci_quirks[] = {
> {
> @@ -214,6 +223,13 @@ static int ohci_quirk_amd700(struct usb_hcd *hcd)
> PCI_DEVICE(PCI_VENDOR_ID_ATI, 0x4399),
> .driver_data = (unsigned long)ohci_quirk_amd700,
> },
> + {
> + .vendor = PCI_VENDOR_ID_APPLE,
> + .device = 0x003f,
> + .subvendor = PCI_SUBVENDOR_ID_REDHAT_QUMRANET,
> + .subdevice = PCI_SUBDEVICE_ID_QEMU,
> + .driver_data = (unsigned long)ohci_quirk_qemu,
> + },
>
> /* FIXME for some of the early AMD 760 southbridges, OHCI
> * won't work at all. blacklist them.
> diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h
> index 37f1725..a51b189 100644
> --- a/drivers/usb/host/ohci.h
> +++ b/drivers/usb/host/ohci.h
> @@ -418,6 +418,7 @@ struct ohci_hcd {
> #define OHCI_QUIRK_AMD_PLL 0x200 /* AMD PLL quirk*/
> #define OHCI_QUIRK_AMD_PREFETCH 0x400 /* pre-fetch for ISO transfer */
> #define OHCI_QUIRK_GLOBAL_SUSPEND 0x800 /* must suspend ports */
> +#define OHCI_QUIRK_QEMU 0x1000 /* relax timing expectations */
>
> // there are also chip quirks/bugs in init logic
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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