openwrt/target/linux/bcm27xx/patches-4.19/950-0666-xhci-Use-more-event-ring-segment-table-entries.patch
Adrian Schmutzler 7d7aa2fd92 brcm2708: rename target to bcm27xx
This change makes the names of Broadcom targets consistent by using
the common notation based on SoC/CPU ID (which is used internally
anyway), bcmXXXX instead of brcmXXXX.
This is even used for target TITLE in make menuconfig already,
only the short target name used brcm so far.

Despite, since subtargets range from bcm2708 to bcm2711, it seems
appropriate to use bcm27xx instead of bcm2708 (again, as already done
for BOARDNAME).

This also renames the packages brcm2708-userland and brcm2708-gpu-fw.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Álvaro Fernández Rojas <noltari@gmail.com>
2020-02-14 14:10:51 +01:00

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2.6 KiB
Diff

From c2e02902a3b75b24306dac06cb6f75b683fa0267 Mon Sep 17 00:00:00 2001
From: Jonathan Bell <jonathan@raspberrypi.org>
Date: Tue, 13 Aug 2019 15:53:29 +0100
Subject: [PATCH] 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 <jonathan@raspberrypi.org>
---
drivers/usb/host/xhci-mem.c | 8 +++++---
drivers/usb/host/xhci.h | 4 ++--
2 files changed, 7 insertions(+), 5 deletions(-)
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2495,9 +2495,11 @@ int xhci_mem_init(struct xhci_hcd *xhci,
* Event ring setup: Allocate a normal ring, but also setup
* the event ring segment table (ERST). Section 4.9.3.
*/
+ val2 = 1 << HCS_ERST_MAX(xhci->hcs_params2);
+ val2 = min_t(unsigned int, ERST_MAX_SEGS, val2);
xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Allocating event ring");
- xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, 1, TYPE_EVENT,
- 0, flags);
+ xhci->event_ring = xhci_ring_alloc(xhci, val2, 1, TYPE_EVENT,
+ 0, flags);
if (!xhci->event_ring)
goto fail;
if (xhci_check_trb_in_td_math(xhci) < 0)
@@ -2510,7 +2512,7 @@ int xhci_mem_init(struct xhci_hcd *xhci,
/* set ERST count with the number of entries in the segment table */
val = readl(&xhci->ir_set->erst_size);
val &= ERST_SIZE_MASK;
- val |= ERST_NUM_SEGS;
+ val |= val2;
xhci_dbg_trace(xhci, trace_xhci_dbg_init,
"// Write ERST size = %i to ir_set 0 (some bits preserved)",
val);
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1643,8 +1643,8 @@ struct urb_priv {
* Each segment table entry is 4*32bits long. 1K seems like an ok size:
* (1K bytes * 8bytes/bit) / (4*32 bits) = 64 segment entries in the table,
* meaning 64 ring segments.
- * Initial allocated size of the ERST, in number of entries */
-#define ERST_NUM_SEGS 1
+ * Maximum number of segments in the ERST */
+#define ERST_MAX_SEGS 8
/* Initial allocated size of the ERST, in number of entries */
#define ERST_SIZE 64
/* Initial number of event segment rings allocated */