patch "ohci-pci: add qemu quirk" added to usb-next

PATCH [email protected] 1 participant 1 message Mar 23, 2017

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Stable branch USB USB ohci driver

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2017-03-23 09:00 UTC #0 lore raw

This is a note to let you know that I've just added the patch titled

ohci-pci: add qemu quirk

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release during the merge window.

If you have any questions about this process, please let me know.

Quoted 1 line

From 21a60f6e65181cad64fd66ccc8080d413721ba27 Mon Sep 17 00:00:00 2001

From: Gerd Hoffmann <[email protected]>
Date: Mon, 20 Mar 2017 09:11:49 +0100
Subject: ohci-pci: add qemu quirk

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 <[email protected]>

Signed-off-by Alan Stern <[email protected]>

Cc stable <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 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(-)

drivers/usb/host/ohci-hcd.c +2 -1

index da66ad57e370..44924824fa41 100644
@@ -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);

drivers/usb/host/ohci-pci.c +16 -0

index bb1509675727..a84aebe9b0a9 100644
@@ -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 const struct pci_device_id ohci_pci_quirks[] = {
 		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.

drivers/usb/host/ohci.h +1 -0

index 382444c8b44c..12742d002d2d 100644
@@ -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

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