[PATCH] Make USB process hub events in correct order
From: Byron Stanoszek
Date: Tue Jun 15 2004 - 13:32:57 EST
This patch fixes the USB hub module to process events in the order that they
are received. It fixes the case where multi-port devices have multiple
hubs in them--while they are detected in the correct order, they are
initialized in reverse. It is required for the Sealink 8-port USB->serial hubs
to initialize with the port numbers in the correct order.
I don't think it breaks any existing functionality, but I won't send this to
Linus yet till I know it doesn't break anything.
Patch below against 2.6.7-rc3.
--- linux/drivers/usb/core/hub.bak 2004-06-08 10:21:57.000000000 -0400
+++ linux/drivers/usb/core/hub.c 2004-06-08 10:59:34.000000000 -0400
@@ -260,7 +260,7 @@
/* Something happened, let khubd figure it out */
if (list_empty(&hub->event_list)) {
- list_add(&hub->event_list, &hub_event_list);
+ list_add_tail(&hub->event_list, &hub_event_list);
wake_up(&khubd_wait);
}
An example without the patch (1-1.2.1 gets initialized before 1-1.1.1):
usb 1-1: new full speed USB device using address 2
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
usb 1-1.1: new full speed USB device using address 3
hub 1-1.1:1.0: USB hub found
hub 1-1.1:1.0: 4 ports detected
usb 1-1.2: new full speed USB device using address 4
hub 1-1.2:1.0: USB hub found
hub 1-1.2:1.0: 4 ports detected
usb 1-1.2.1: new full speed USB device using address 5
ftdi_sio 1-1.2.1:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.1: FTDI FT232BM Compatible converter now attached to ttyUSB0 (or usb/tts/0 for devfs)
usb 1-1.2.2: new full speed USB device using address 6
ftdi_sio 1-1.2.2:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.2: FTDI FT232BM Compatible converter now attached to ttyUSB1 (or usb/tts/1 for devfs)
usb 1-1.2.3: new full speed USB device using address 7
ftdi_sio 1-1.2.3:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.3: FTDI FT232BM Compatible converter now attached to ttyUSB2 (or usb/tts/2 for devfs)
usb 1-1.2.4: new full speed USB device using address 8
ftdi_sio 1-1.2.4:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.4: FTDI FT232BM Compatible converter now attached to ttyUSB3 (or usb/tts/3 for devfs)
usb 1-1.1.1: new full speed USB device using address 9
ftdi_sio 1-1.1.1:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.1: FTDI FT232BM Compatible converter now attached to ttyUSB4 (or usb/tts/4 for devfs)
usb 1-1.1.2: new full speed USB device using address 10
ftdi_sio 1-1.1.2:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.2: FTDI FT232BM Compatible converter now attached to ttyUSB5 (or usb/tts/5 for devfs)
usb 1-1.1.3: new full speed USB device using address 11
ftdi_sio 1-1.1.3:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.3: FTDI FT232BM Compatible converter now attached to ttyUSB6 (or usb/tts/6 for devfs)
usb 1-1.1.4: new full speed USB device using address 12
ftdi_sio 1-1.1.4:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.4: FTDI FT232BM Compatible converter now attached to ttyUSB7 (or usb/tts/7 for devfs)
With the patch (the correct ordering):
usb 1-1: new full speed USB device using address 2
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
usb 1-1.1: new full speed USB device using address 3
hub 1-1.1:1.0: USB hub found
hub 1-1.1:1.0: 4 ports detected
usb 1-1.2: new full speed USB device using address 4
hub 1-1.2:1.0: USB hub found
hub 1-1.2:1.0: 4 ports detected
usb 1-1.1.1: new full speed USB device using address 5
ftdi_sio 1-1.1.1:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.1: FTDI FT232BM Compatible converter now attached to ttyUSB0 (or usb/tts/0 for devfs)
usb 1-1.1.2: new full speed USB device using address 6
ftdi_sio 1-1.1.2:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.2: FTDI FT232BM Compatible converter now attached to ttyUSB1 (or usb/tts/1 for devfs)
usb 1-1.1.3: new full speed USB device using address 7
ftdi_sio 1-1.1.3:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.3: FTDI FT232BM Compatible converter now attached to ttyUSB2 (or usb/tts/2 for devfs)
usb 1-1.1.4: new full speed USB device using address 8
ftdi_sio 1-1.1.4:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.1.4: FTDI FT232BM Compatible converter now attached to ttyUSB3 (or usb/tts/3 for devfs)
usb 1-1.2.1: new full speed USB device using address 9
ftdi_sio 1-1.2.1:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.1: FTDI FT232BM Compatible converter now attached to ttyUSB4 (or usb/tts/4 for devfs)
usb 1-1.2.2: new full speed USB device using address 10
ftdi_sio 1-1.2.2:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.2: FTDI FT232BM Compatible converter now attached to ttyUSB5 (or usb/tts/5 for devfs)
usb 1-1.2.3: new full speed USB device using address 11
ftdi_sio 1-1.2.3:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.3: FTDI FT232BM Compatible converter now attached to ttyUSB6 (or usb/tts/6 for devfs)
usb 1-1.2.4: new full speed USB device using address 12
ftdi_sio 1-1.2.4:1.0: FTDI FT232BM Compatible converter detected
usb 1-1.2.4: FTDI FT232BM Compatible converter now attached to ttyUSB7 (or usb/tts/7 for devfs)
-Byron
--
Byron Stanoszek Ph: (330) 644-3059
Systems Programmer Fax: (330) 644-8110
Commercial Timesharing Inc. Email: byron@xxxxxxxxxxx--- linux/drivers/usb/core/hub.bak 2004-06-08 10:21:57.000000000 -0400
+++ linux/drivers/usb/core/hub.c 2004-06-08 10:59:34.000000000 -0400
@@ -260,7 +260,7 @@
/* Something happened, let khubd figure it out */
if (list_empty(&hub->event_list)) {
- list_add(&hub->event_list, &hub_event_list);
+ list_add_tail(&hub->event_list, &hub_event_list);
wake_up(&khubd_wait);
}