diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0259-lan78xx-Debounce-link-events-to-minimize-poll-storm.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0259-lan78xx-Debounce-link-events-to-minimize-poll-storm.patch | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0259-lan78xx-Debounce-link-events-to-minimize-poll-storm.patch b/target/linux/brcm2708/patches-4.19/950-0259-lan78xx-Debounce-link-events-to-minimize-poll-storm.patch new file mode 100644 index 0000000000..395934dd49 --- /dev/null +++ b/target/linux/brcm2708/patches-4.19/950-0259-lan78xx-Debounce-link-events-to-minimize-poll-storm.patch @@ -0,0 +1,44 @@ +From 020ee4d0d438b830ee40da8d9d3414de156a11e7 Mon Sep 17 00:00:00 2001 +From: Joshua Emele <jemele@acm.org> +Date: Wed, 7 Nov 2018 16:07:40 -0800 +Subject: [PATCH] lan78xx: Debounce link events to minimize poll storm + +The bInterval is set to 4 (i.e. 8 microframes => 1ms) and the only bit +that the driver pays attention to is "link was reset". If there's a +flapping status bit in that endpoint data, (such as if PHY negotiation +needs a few tries to get a stable link) then polling at a slower rate +would act as a de-bounce. + +See: https://github.com/raspberrypi/linux/issues/2447 +--- + drivers/net/usb/lan78xx.c | 12 +++++++++++- + 1 file changed, 11 insertions(+), 1 deletion(-) + +--- a/drivers/net/usb/lan78xx.c ++++ b/drivers/net/usb/lan78xx.c +@@ -449,6 +449,11 @@ static bool enable_tso; + module_param(enable_tso, bool, 0644); + MODULE_PARM_DESC(enable_tso, "Enables TCP segmentation offload"); + ++#define INT_URB_MICROFRAMES_PER_MS 8 ++static int int_urb_interval_ms = 8; ++module_param(int_urb_interval_ms, int, 0); ++MODULE_PARM_DESC(int_urb_interval_ms, "Override usb interrupt urb interval"); ++ + static int lan78xx_read_reg(struct lan78xx_net *dev, u32 index, u32 *data) + { + u32 *buf = kmalloc(sizeof(u32), GFP_KERNEL); +@@ -3838,7 +3843,12 @@ static int lan78xx_probe(struct usb_inte + dev->pipe_intr = usb_rcvintpipe(dev->udev, + dev->ep_intr->desc.bEndpointAddress & + USB_ENDPOINT_NUMBER_MASK); +- period = dev->ep_intr->desc.bInterval; ++ if (int_urb_interval_ms <= 0) ++ period = dev->ep_intr->desc.bInterval; ++ else ++ period = int_urb_interval_ms * INT_URB_MICROFRAMES_PER_MS; ++ ++ netif_notice(dev, probe, netdev, "int urb period %d\n", period); + + maxp = usb_maxpacket(dev->udev, dev->pipe_intr, 0); + buf = kmalloc(maxp, GFP_KERNEL); |