Am 16.03.2011 20:34, schrieb Greg KH: > On Wed, Mar 16, 2011 at 07:28:25PM +0100, Johan Hovold wrote: >> On Wed, Mar 16, 2011 at 08:23:11AM -0700, Greg KH wrote: >>> On Wed, Mar 16, 2011 at 03:48:53PM +0100, Sven Köhler wrote: >>>> Hi, >>>> >>>> I'm not sure, whether you consider this is an issue. However, the device >>>> I have (Lego NXT in SAM-BA mode, lsusb shows it as 03eb:6124 Atmel Corp. >>>> at91sam SAMBA bootloader) is supported by both cdc_acm and sam_ba kernel >>>> modules, which leads to unpredictable behaviour. >>>> (Tested 2.6.38 - same issue in 2.6.37) >>> >>> I think Johan is the best one to answer this, as he submitted the sam-ba >>> driver. >>> >>> Johan, any thoughts on the below info? >>> >>> >>>> >>>> If I plug the device in, the following happens if cdc_acm is already loaded: >>>>> usb 4-1: new full speed USB device using uhci_hcd and address 3 >>>>> cdc_acm 4-1:1.0: This device cannot do calls on its own. It is not a modem. >>>>> cdc_acm 4-1:1.0: ttyACM0: USB ACM device >>>>> usbcore: registered new interface driver cdc_acm >>>>> cdc_acm: v0.26:USB Abstract Control Model driver for USB modems and ISDN adapters >>>>> USB Serial support registered for sam-ba >>>>> usbcore: registered new interface driver sam-ba >>>>> sam_ba: v1.0: Atmel SAM Boot Assistant (SAM-BA) driver >>>> >>>> After unloading both cdc_acm and sam_ba, the following happends: >>>>> usb 4-1: new full speed USB device using uhci_hcd and address 4 >>>>> USB Serial support registered for sam-ba >>>>> sam-ba 4-1:1.1: sam-ba converter detected >>>>> usb 4-1: sam-ba converter now attached to ttyUSB0 >>>>> usbcore: registered new interface driver sam-ba >>>>> sam_ba: v1.0: Atmel SAM Boot Assistant (SAM-BA) driver >>>>> cdc_acm 4-1:1.0: This device cannot do calls on its own. It is not a modem. >>>>> cdc_acm: probe of 4-1:1.0 failed with error -16 >>>>> usbcore: registered new interface driver cdc_acm >>>>> cdc_acm: v0.26:USB Abstract Control Model driver for USB modems and ISDN adapters >>>> >>>> As you can see, the device is recognized by cdc_acm as well as sam_ba. >>>> Depending on which module is loaded, the device is either claimed by >>>> cdc_acm or sam_ba. The device name may be either ttyACM* or ttyUSB* >> >> Tradionally the generic usb-serial driver was used to access the SAM-BA >> boot application; this is documented in the Atmel tools, which also >> expect the device to show up as a ttyUSBx node. Due to changes in the >> generic driver the tools stopped working from 2.6.32 and a dedicated >> driver was later written (sam-ba). >> >> A couple of weeks after the sam-ba driver was submitted, however, >> 5b239f0aebd4dd6f85b13decf5e18e86e35d57f0 (USB: cdc-acm: Add pseudo modem >> without AT command capabilities) was submitted, which causes cdc_acm to >> bind to these devices as well. >> >>>> I have no clue, whether there are Atmel SAM-BA implementations that do >>>> not support the cdc profile. >>>> >>>> I'm not sure, whether the device should be blacklisted in cdc_acm in >>>> favor of sam_ba. However, I have the feeling that if sam_ba is actually >>>> installed, sam_ba should claim the device even if cdc_acm is already loaded. >>>> >>>> Last time I tested, the device was working fine with cdc_acm, though. >> >> I just connected a at91sam9260-ek board and can confirm that the samba >> tools do seem to work with the cdc-acm driver, although it does require >> a ttyUSBx symlink for the device to be recognised by the user-space tools >> (latest v2.10). >> >> I'm not sure about how to proceed with this. What do you say, Greg? > > If the sam-ba driver is not needed, we can just remove it. > > The symlink issue should be fixable in the userspace tools to just get > it to look for the different port (it should never have hard-coded > ttyUSB0 anyway, what if it was on ttyUSB3?). It's an UI issue, basically. They show a list of devices and they only show the ones matching the pattern ttyUSB*. In addition, you can't enter a custom device name. That's why you have to create a symlink, for example from ttyACM3 to ttyUSB7. Regards, Sven
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