On 08/04/2015 10:00 PM, arun k wrote: > I enabled software flow control like below > > tty.c_iflag |= (IXON | IXOFF | IXANY); Ok, but does the sending device know how to process in-band software flow control and is it set up to respond properly? Also, I doubt software flow control is going to work @ 4Mbaud line rate. If you're stuck using software flow control, start with a 115kbaud line rate and see if that fixes your data loss problem. Regards, Peter Hurley > On Wed, Aug 5, 2015 at 12:59 AM, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote: >> On 08/03/2015 10:47 PM, arun k wrote: >>> Thank you for the reply >>> >>>>> The tty layer is limiting you, just keep reading in a loop until you >>>>> run out of data, you should not ever expect to read a specific number of >>>>> bytes from a tty device at a time, the read call will tell you the >>>>> number that was read properly. >>> >>> I tried this method but in my case I found data loss. By changing any buffer size modification in driver side , can we fix this issue ? >> >> The data loss is probably occurring because you have all flow control disabled >> and the line speed is too fast for no flow control. >> >> Regards, >> Peter Hurley >> >>>>> Please don't use the "generic" driver, it's slow and not the best to >>>>> use >>> >>> Could you tell me is generic driver is suitable for my application ( My usb device sending data at a rate of 409600 bytes/sec) , ? >>> or do you have any other suggestion for me ? >>> >>> My Linux kernel version is 3.4.35 >>> >>> Regards, >>> Arun >>> >>> On Tue, Aug 4, 2015 at 1:13 AM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx <mailto:gregkh@xxxxxxxxxxxxxxxxxxx>> wrote: >>> >>> On Mon, Aug 03, 2015 at 04:44:07PM +0900, arun k wrote: >>> > Hi , >>> > >>> > I have a trouble with using usb serial generic device. >>> > I am using USB - Generic Serial driver for communicating with my usb >>> > device and my embedded device. >>> >>> Please don't use the "generic" driver, it's slow and not the best to >>> use. >>> >>> > My usb device sending data at a rate of 409600 bytes/sec, and in host >>> > side application I tried to read 16384 bytes in one read. But the read >>> > size returning is always 4095 >>> >>> The tty layer is limiting you, just keep reading in a loop until you >>> run out of data, you should not ever expect to read a specific number of >>> bytes from a tty device at a time, the read call will tell you the >>> number that was read properly. >>> >>> thanks, >>> >>> greg k-h >>> >>> >> -- 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
