From 755387ee31d8638089dd2791de82e4737dc79333 Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@osmocom.org>
Date: Wed, 26 Jan 2022 13:56:44 +0100
Subject: [PATCH] Reduce bInterval of interrupt endpoints to avoid interrupt
 misses

Particularly the VCC/RST/CLK changes can happen quite frequent, and
we were seeing quite a number of overflows of the usb_buf queue for EP06
(interrupt endpoint) in cardem.

I first tried increasing the maximum queue size to up to 10, but that
still didn't resolve those EP06 overflow error log messages.

Reducing the bInterval from 16 to 1 made them go away in all my
tests.

Change-Id: I5c272c31983de7201cfbd445c4484f6832d878ab
---
 firmware/libcommon/source/usb.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/firmware/libcommon/source/usb.c b/firmware/libcommon/source/usb.c
index d86fc923..7a99b158 100644
--- a/firmware/libcommon/source/usb.c
+++ b/firmware/libcommon/source/usb.c
@@ -206,7 +206,7 @@ static const SIMTraceDriverConfigurationDescriptorSniffer
 						SIMTRACE_USB_EP_CARD_INT),
 		.bmAttributes		= USBEndpointDescriptor_INTERRUPT,
 		.wMaxPacketSize	= USBEndpointDescriptor_MAXINTERRUPTSIZE_FS,
-		.bInterval = 0x10,
+		.bInterval = 1,
 	},
 	DFURT_IF_DESCRIPTOR(1, 0),
 };
@@ -382,7 +382,7 @@ static const SIMTraceDriverConfigurationDescriptorPhone
 						SIMTRACE_CARDEM_USB_EP_USIM1_INT),
 		.bmAttributes		= USBEndpointDescriptor_INTERRUPT,
 		.wMaxPacketSize		= USBEndpointDescriptor_MAXINTERRUPTSIZE_FS,
-		.bInterval		= 0x10
+		.bInterval		= 1
 	},
 #ifdef CARDEMU_SECOND_UART
 	/* Communication class interface standard descriptor */
@@ -429,7 +429,7 @@ static const SIMTraceDriverConfigurationDescriptorPhone
 						SIMTRACE_CARDEM_USB_EP_USIM2_INT),
 		.bmAttributes		= USBEndpointDescriptor_INTERRUPT,
 		.wMaxPacketSize		= USBEndpointDescriptor_MAXINTERRUPTSIZE_FS,
-		.bInterval		= 0x10,
+		.bInterval		= 1,
 	},
 	DFURT_IF_DESCRIPTOR(2, 0),
 #else
@@ -547,7 +547,7 @@ static const SIMTraceDriverConfigurationDescriptorMITM
 						      CCID_EPT_NOTIFICATION),
 		.bmAttributes		= USBEndpointDescriptor_INTERRUPT,
 		.wMaxPacketSize = USBEndpointDescriptor_MAXINTERRUPTSIZE_FS,
-		.bInterval = 0x10,
+		.bInterval = 1,
 	},
 
 	/* Communication class interface standard descriptor */
@@ -593,7 +593,7 @@ static const SIMTraceDriverConfigurationDescriptorMITM
 						SIMTRACE_USB_EP_PHONE_INT),
 		.bmAttributes		= USBEndpointDescriptor_INTERRUPT,
 		.wMaxPacketSize		= USBEndpointDescriptor_MAXINTERRUPTSIZE_FS,
-		.bInterval		= 0x10
+		.bInterval		= 1
 	},
 	DFURT_IF_DESCRIPTOR(2, 0),
 };