From 41ba0febc5d69b5867ce1ad0b0852a0f59e16d16 Mon Sep 17 00:00:00 2001 From: Jonathan Bell Date: Thu, 19 Oct 2023 13:29:10 +0300 Subject: [PATCH 403/697] xhci: Use more event ring segment table entries Users have reported log spam created by "Event Ring Full" xHC event TRBs. These are caused by interrupt latency in conjunction with a very busy set of devices on the bus. The errors are benign, but throughput will suffer as the xHC will pause processing of transfers until the event ring is drained by the kernel. Expand the number of event TRB slots available by increasing the number of event ring segments in the ERST. Controllers have a hardware-defined limit as to the number of ERST entries they can process, so make the actual number in use min(ERST_MAX_SEGS, hw_max). Signed-off-by: Jonathan Bell --- drivers/usb/host/xhci.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1392,7 +1392,7 @@ struct urb_priv { }; /* Number of Event Ring segments to allocate, when amount is not specified. (spec allows 32k) */ -#define ERST_DEFAULT_SEGS 2 +#define ERST_DEFAULT_SEGS 8 /* Poll every 60 seconds */ #define POLL_TIMEOUT 60 /* Stop endpoint command timeout (secs) for URB cancellation watchdog timer */