patch "usb: xhci: do not perform Soft Retry for some xHCI hosts" added to usb-linus

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

usb: xhci: do not perform Soft Retry for some xHCI hosts

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-linus 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 hopefully also be merged in Linus's tree for the next -rc kernel release.

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

From a4a251f8c23518899d2078c320cf9ce2fa459c9f Mon Sep 17 00:00:00 2001
From: Stanislaw Gruszka <[email protected]>
Date: Thu, 11 Mar 2021 13:53:50 +0200
Subject: usb: xhci: do not perform Soft Retry for some xHCI hosts

On some systems rt2800usb and mt7601u devices are unable to operate since commit f8f80be501aa ("xhci: Use soft retry to recover faster from transaction errors")

Seems that some xHCI controllers can not perform Soft Retry correctly, affecting those devices.

To avoid the problem add xhci->quirks flag that restore pre soft retry xhci behaviour for affected xHCI controllers. Currently those are AMD_PROMONTORYA_4 and AMD_PROMONTORYA_2, since it was confirmed by the users: on those xHCI hosts issue happen and is gone after disabling Soft Retry.

[minor commit message rewording for checkpatch -Mathias]

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202541

---
 drivers/usb/host/xhci-pci.c  | 5 +++++
 drivers/usb/host/xhci-ring.c | 3 ++-
 drivers/usb/host/xhci.h      | 1 +
 3 files changed, 8 insertions(+), 1 deletion(-)

index 84da8406d5b4..1f989a49c8c6 100644
@@ -295,6 +295,11 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	     pdev->device == 0x9026)
 		xhci->quirks |= XHCI_RESET_PLL_ON_DISCONNECT;
 
+	if (pdev->vendor == PCI_VENDOR_ID_AMD &&
+	    (pdev->device == PCI_DEVICE_ID_AMD_PROMONTORYA_2 ||
+	     pdev->device == PCI_DEVICE_ID_AMD_PROMONTORYA_4))
+		xhci->quirks |= XHCI_NO_SOFT_RETRY;
+
 	if (xhci->quirks & XHCI_RESET_ON_RESUME)
 		xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
 				"QUIRK: Resetting on resume");

index 5e548a1c93ab..ce38076901e2 100644
@@ -2484,7 +2484,8 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		remaining	= 0;
 		break;
 	case COMP_USB_TRANSACTION_ERROR:
-		if ((ep_ring->err_count++ > MAX_SOFT_RETRY) ||
+		if (xhci->quirks & XHCI_NO_SOFT_RETRY ||
+		    (ep_ring->err_count++ > MAX_SOFT_RETRY) ||
 		    le32_to_cpu(slot_ctx->tt_info) & TT_SLOT)
 			break;
 

index d41de5dc0452..ca822ad3b65b 100644
@@ -1891,6 +1891,7 @@ struct xhci_hcd {
 #define XHCI_SKIP_PHY_INIT	BIT_ULL(37)
 #define XHCI_DISABLE_SPARSE	BIT_ULL(38)
 #define XHCI_SG_TRB_CACHE_SIZE_QUIRK	BIT_ULL(39)
+#define XHCI_NO_SOFT_RETRY	BIT_ULL(40)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;

2.30.2