lkml.org 
[lkml]   [2006]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [LinuxBIOS] [linux-usb-devel] [RFC][PATCH 0/2] x86_64 Early usb debug port support.
On Wed, Dec 06, 2006 at 01:08:14PM -0800, Lu, Yinghai wrote:
> -----Original Message-----
> From: Andi Kleen [mailto:ak@suse.de]
> Sent: Wednesday, December 06, 2006 12:59 PM
>
> >I haven't looked how the other usb_debug works -- if it's polled
> >too then it wouldn't have much advantage.
>
> Need to verify if the two sides of debug cable are identical.

I got my device yesterday and after a small plugfest I can confirm
that only one end of the device enumerates when connected to an ICH7
EHCI driven by 2.6.19.

--8<--
Bus 001 Device 027: ID 0525:127a Netchip Technology, Inc.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x0525 Netchip Technology, Inc.
idProduct 0x127a
bcdDevice 1.01
iManufacturer 1 NetChip
iProduct 2 NetChip TurboCONNECT 2.0
iSerial 3 1
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 0mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
bNumConfigurations 1
Debug descriptor:
bLength 4
bDescriptorType 10
bDebugInEndpoint 0x82
bDebugOutEndpoint 0x01
-->8--

The device is in fact not self-powered.

My theory is that the same set of descriptors are used for both ends,
but one end has been locked to address 127 in order to work with
simpler debug port drivers that assume it will be there.

I guess that the self-powered error is also to simplify life for
debug port drivers. IIRC most if not all USB power management
concerns are noops for debug ports.


//Peter
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-12-07 10:53    [W:0.030 / U:1.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site