--- On Fri, 5/14/10, Ron Madrid <ron_madrid@xxxxxxxxxxxxx> wrote: > From: Ron Madrid <ron_madrid@xxxxxxxxxxxxx> > Subject: Re: g_serial and cdc_acm communications > To: "Rob Duncan" <Robert.Duncan@xxxxxxxx> > Cc: "Oliver Neukum" <oliver@xxxxxxxxxx>, "linux-usb@xxxxxxxxxxxxxxx" <linux-usb@xxxxxxxxxxxxxxx> > Date: Friday, May 14, 2010, 2:22 PM > --- On Thu, 5/13/10, Ron Madrid > <ron_madrid@xxxxxxxxxxxxx> > wrote: > > > From: Ron Madrid <ron_madrid@xxxxxxxxxxxxx> > > Subject: Re: g_serial and cdc_acm communications > > To: "Rob Duncan" <Robert.Duncan@xxxxxxxx> > > Cc: "Oliver Neukum" <oliver@xxxxxxxxxx>, > "linux-usb@xxxxxxxxxxxxxxx" > <linux-usb@xxxxxxxxxxxxxxx> > > Date: Thursday, May 13, 2010, 2:03 PM > > --- On Thu, 5/13/10, Ron Madrid > > <ron_madrid@xxxxxxxxxxxxx> > > wrote: > > > > Another wrinkle in all of this ... I just tried > write()ing > > the exact same number of bytes and everything appeared > to > > work flawlessly. > > I noticed that when I was doing write() to the tty device, > the > USB device was performing Bo with 512 bytes at a time, > read() > seemed to do 1024 at a time. Is there a way that I > could > change the USB Bi buffer to 512 and see if that fixes > anything? Or does this possible mean anything? Below is the description of the 'device' on my host machine. It says that the Bi and Bo MxPS is 512, however when I do transfers I see transfer sizes of 1024 for reads and 512 for writes with usbmon. Writes seem to work fine but reads are where the problem lies. T: Bus=01 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#= 2 Spd=480 MxCh= 0 D: Ver= 2.00 Cls=02(comm.) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 P: Vendor=0525 ProdID=a4a7 Rev=24.19 S: Manufacturer=Linux 2.6.33-rc1-01541-g4dc3fe1-dirty with fsl-us S: Product=Gadget Serial v2.4 C:* #Ifs= 2 Cfg#= 2 Atr=c0 MxPwr=500mA I: If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=cdc_acm E: Ad=82(I) Atr=03(Int.) MxPS= 10 Ivl=32ms I: If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_acm E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms E: Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms Could this be the root of my problem? Is there a way to change the size of the buffer for the Bi? Ron -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
