RE: [PATCH] USB: Mass Storage: Add MediaTek MT6276M device entry

From: Meng Zhang (张萌)
Date: Wed Feb 29 2012 - 01:04:34 EST


Hi Matthew,

Thanks for your comment, I've tested some other products and found their entries in /lib/udev/rules.d/40-usb_modeswitch.rules.
So, does usb_modeswitch comes with latest distributions by default?

Thanks!

BR.
Meng Zhang


-----Original Message-----
From: Matthew Dharm [mailto:mdharm-usb@xxxxxxxxxxxxxxxxxx]
Sent: Wednesday, February 29, 2012 12:08 PM
To: Meng Zhang (张萌)
Cc: Alan Stern; Josua Dietze; Phil Dibowitz; USB list; USB Storage list; Kernel development list
Subject: Re: [PATCH] USB: Mass Storage: Add MediaTek MT6276M device entry

Devices should not be added to unusual_devs.h unless the device CANNOT use the usb_modeswitch method. This most commonly applies when the device's usb-storage emulation is poor, and the probing commands sent by usb-storage cause the device to crash.

It is much more convenient for users to just upgrade their usb_modeswitch utility than it is for them to upgrade a kernel, which is much more difficult and much more rare. As for 'input command manually', that is what udev scripts are for.

If this can be handled from userspace by usb_modeswitch, then that is where it should be done.

Matt

2012/2/28 Meng Zhang (张萌) <Meng.Zhang@xxxxxxxxxxxx>:
> Hi Alan,
>
> As far as I know, many other devices used this init function in unusual_devs.h for their "ZeroCD" feature, and I think this is more convenient than let device user install utilities like usb_modeswitch and input command manually.
>
> Thanks.
>
> BR.
> Meng Zhang
>
> -----Original Message-----
> From: linux-usb-owner@xxxxxxxxxxxxxxx
> [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Alan Stern
> Sent: Tuesday, February 28, 2012 11:31 PM
> To: Meng Zhang (张萌)
> Cc: Josua Dietze; Matthew Dharm; Phil Dibowitz; USB list; USB Storage
> list; Kernel development list
> Subject: Re: [PATCH] USB: Mass Storage: Add MediaTek MT6276M device
> entry
>
> On Tue, 28 Feb 2012, Meng Zhang wrote:
>
>> from: Meng Zhang <meng.zhang@xxxxxxxxxxxx>
>>
>> 1. Add entrys for mediatek MT6276M in unusual_devs.h
>>
>> 2. Add init function for mediatek MT6276M to switch to COM port mode
>>
>> 3. usb-devices outputs after running with this patch:
>> T: Bus=02 Lev=01 Prnt=01 Port=05 Cnt=01 Dev#= 48 Spd=480 MxCh= 0
>> D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
>> P: Vendor=0e8d ProdID=00a1 Rev=02.00
>> S: Manufacturer=MediaTek Inc
>> S: Product=Product
>> C: #Ifs= 3 Cfg#= 1 Atr=80 MxPwr=500mA
>> I: If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=02 Prot=01 Driver=option
>> I: If#= 1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
>> I: If#= 2 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
>>
>> 4. patch based on branch:
>>
>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>
>>
>> Signed-off-by: Meng Zhang <meng.zhang@xxxxxxxxxxxx>
>
> Nowadays, aren't such things handled in userspace by the usb_modeswitch program rather than in the kernel driver?
>
> Alan Stern
>
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--
Matthew Dharm
Maintainer, USB Mass Storage driver for Linux
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