On Tue, Jan 16, 2024, Prashanth K wrote:

Upstream commit bac1ec551434 ("usb: xhci: Set quirk for XHCI_SG_TRB_CACHE_SIZE_QUIRK") introduced a new quirk in XHCI which fixes XHC timeout, which was seen on synopsys XHCs while using SG buffers. But the support for this quirk isn't present in the DWC3 layer.

We will encounter this XHCI timeout/hung issue if we run iperf loopback tests using RTL8156 ethernet adaptor on DWC3 targets with scatter-gather enabled. This gets resolved after enabling the XHCI_SG_TRB_CACHE_SIZE_QUIRK. This patch enables it using the xhci device property since its needed for DWC3 controller.

In Synopsys DWC3 databook, Table 9-3: xHCI Debug Capability Limitations Chained TRBs greater than TRB cache size: The debug capability driver must not create a multi-TRB TD that describes smaller than a 1K packet that spreads across 8 or more TRBs on either the IN TR or the OUT TR.

Cc: stable@vger.kernel.org #5.11 Signed-off-by: Prashanth K quic_prashk@quicinc.com

---

drivers/usb/dwc3/host.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c index 61f57fe5bb78..43230915323c 100644 --- a/drivers/usb/dwc3/host.c +++ b/drivers/usb/dwc3/host.c @@ -61,7 +61,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc) int dwc3_host_init(struct dwc3 *dwc) {

• struct property_entry props[4];

• struct property_entry props[5]; struct platform_device *xhci; int ret, irq; int prop_idx = 0;

@@ -89,6 +89,8 @@ int dwc3_host_init(struct dwc3 *dwc) memset(props, 0, sizeof(struct property_entry) * ARRAY_SIZE(props));

• props[prop_idx++] = PROPERTY_ENTRY_BOOL("xhci-sg-trb-cache-size-quirk");
• if (dwc->usb3_lpm_capable) props[prop_idx++] = PROPERTY_ENTRY_BOOL("usb3-lpm-capable");

2.25.1

Acked-by: Thinh Nguyen Thinh.Nguyen@synopsys.com

Thanks, Thinh