Re: serial and tty driver
On Sun, Feb 18, 2007 at 11:52:58AM +0300, Mockern wrote: > Thank you for you respond. > > I asked this question since I have one problem with my tty driver. > It based on serial_core.c. It works well except Linux cat operation:(. > (e.g. cat < ttyS10). I thought in tty driver there is no function > for this operation and I wanted to know that maybe serial driver has it. > > Could it be the reason that cat operation in tty driver does not work > (but I can write and read from user space application!)? > Or maybe I need to implement a special function in my tty driver to support > Linux > cat operation? If you do something like "cat < ttyS10" it will work by opening the device just like a user space application --- but the shell, which is opening /dev/ttyS10, won't use any of the special flags that a user space application might use to not wait for the carrier detect line to go high, for example. I'd have to see the sources of the driver and your user space application to be sure, but one thing you should try is "stty -F /dev/ttyS10 clocal" and see if that allows "cat < /dev/ttyS10" to work. Regards, - Ted - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
Thank you for you respond. I asked this question since I have one problem with my tty driver. It based on serial_core.c. It works well except Linux cat operation:(. (e.g. cat < ttyS10). I thought in tty driver there is no function for this operation and I wanted to know that maybe serial driver has it. Could it be the reason that cat operation in tty driver does not work (but I can write and read from user space application!)? Or maybe I need to implement a special function in my tty driver to support Linux cat operation? Thank you again >On Sat, Feb 17, 2007 at 12:24:22PM -0600, Paul Fulghum wrote: >> Mockern wrote: >> >I have a question, what is really difference between serial and tty >> >drivers? >> > >> >As I understand tty is high level and communicates with user space. >> >> The serial core implements many of the details of a tty >> driver in a common place so that individual hardware drivers >> (serial drivers) only need implement the hardware specific code. >> >> This prevents duplicating tty logic in many drivers, >> with the possibility of mistakes/inconsistency in the >> different tty drivers. >> >> The stand alone tty drivers are mostly legacy code from >> the time before serial core that have not been ported >> to be a serial drivers. > >Not necessarily; there are a number of tty drivers, such as the >console drivers and pseudo-tty drivers that have absolutely nothing to >do with an RS-232 port. > >On the other side of the argument, another factorization of the layers >that might have made sense was to move the functionality to the >high-level tty layer (or in the case of hangup code, all the way up to >the VFS layer as a generic sys_revoke functionality), but the reason >why it didn't is largely historical. > > - Ted >- >To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >the body of a message to [EMAIL PROTECTED] >More majordomo info at http://vger.kernel.org/majordomo-info.html >Please read the FAQ at http://www.tux.org/lkml/ -- Яндекс.Почта: объем почтового ящика не ограничен! http://mail.yandex.ru/monitoring/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
Thank you for you respond. I asked this question since I have one problem with my tty driver. It based on serial_core.c. It works well except Linux cat operation:(. (e.g. cat ttyS10). I thought in tty driver there is no function for this operation and I wanted to know that maybe serial driver has it. Could it be the reason that cat operation in tty driver does not work (but I can write and read from user space application!)? Or maybe I need to implement a special function in my tty driver to support Linux cat operation? Thank you again On Sat, Feb 17, 2007 at 12:24:22PM -0600, Paul Fulghum wrote: Mockern wrote: I have a question, what is really difference between serial and tty drivers? As I understand tty is high level and communicates with user space. The serial core implements many of the details of a tty driver in a common place so that individual hardware drivers (serial drivers) only need implement the hardware specific code. This prevents duplicating tty logic in many drivers, with the possibility of mistakes/inconsistency in the different tty drivers. The stand alone tty drivers are mostly legacy code from the time before serial core that have not been ported to be a serial drivers. Not necessarily; there are a number of tty drivers, such as the console drivers and pseudo-tty drivers that have absolutely nothing to do with an RS-232 port. On the other side of the argument, another factorization of the layers that might have made sense was to move the functionality to the high-level tty layer (or in the case of hangup code, all the way up to the VFS layer as a generic sys_revoke functionality), but the reason why it didn't is largely historical. - Ted - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ -- Яндекс.Почта: объем почтового ящика не ограничен! http://mail.yandex.ru/monitoring/ - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
On Sun, Feb 18, 2007 at 11:52:58AM +0300, Mockern wrote: Thank you for you respond. I asked this question since I have one problem with my tty driver. It based on serial_core.c. It works well except Linux cat operation:(. (e.g. cat ttyS10). I thought in tty driver there is no function for this operation and I wanted to know that maybe serial driver has it. Could it be the reason that cat operation in tty driver does not work (but I can write and read from user space application!)? Or maybe I need to implement a special function in my tty driver to support Linux cat operation? If you do something like cat ttyS10 it will work by opening the device just like a user space application --- but the shell, which is opening /dev/ttyS10, won't use any of the special flags that a user space application might use to not wait for the carrier detect line to go high, for example. I'd have to see the sources of the driver and your user space application to be sure, but one thing you should try is stty -F /dev/ttyS10 clocal and see if that allows cat /dev/ttyS10 to work. Regards, - Ted - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
On Sat, Feb 17, 2007 at 12:24:22PM -0600, Paul Fulghum wrote: > Mockern wrote: > >I have a question, what is really difference between serial and tty > >drivers? > > > >As I understand tty is high level and communicates with user space. > > The serial core implements many of the details of a tty > driver in a common place so that individual hardware drivers > (serial drivers) only need implement the hardware specific code. > > This prevents duplicating tty logic in many drivers, > with the possibility of mistakes/inconsistency in the > different tty drivers. > > The stand alone tty drivers are mostly legacy code from > the time before serial core that have not been ported > to be a serial drivers. Not necessarily; there are a number of tty drivers, such as the console drivers and pseudo-tty drivers that have absolutely nothing to do with an RS-232 port. On the other side of the argument, another factorization of the layers that might have made sense was to move the functionality to the high-level tty layer (or in the case of hangup code, all the way up to the VFS layer as a generic sys_revoke functionality), but the reason why it didn't is largely historical. - Ted - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial or tty driver
Mockern wrote: I have a question, what is really difference between serial and tty drivers? As I understand tty is high level and communicates with user space. That's pretty much it, yes. When you're talking to a serial port, you have a stack that looks roughly like: (Userspace) VFS layer tty layer --\ serial core layerline discipline serial driver (Hardware) There are other devices which can exist below the tty layer, like the pty driver: (Userspace) VFS layer tty layer --\ pty driver line discipline -hpa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
Mockern wrote: I have a question, what is really difference between serial and tty drivers? As I understand tty is high level and communicates with user space. The serial core implements many of the details of a tty driver in a common place so that individual hardware drivers (serial drivers) only need implement the hardware specific code. This prevents duplicating tty logic in many drivers, with the possibility of mistakes/inconsistency in the different tty drivers. The stand alone tty drivers are mostly legacy code from the time before serial core that have not been ported to be a serial drivers. -- Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
Mockern wrote: I have a question, what is really difference between serial and tty drivers? As I understand tty is high level and communicates with user space. The serial core implements many of the details of a tty driver in a common place so that individual hardware drivers (serial drivers) only need implement the hardware specific code. This prevents duplicating tty logic in many drivers, with the possibility of mistakes/inconsistency in the different tty drivers. The stand alone tty drivers are mostly legacy code from the time before serial core that have not been ported to be a serial drivers. -- Paul - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial or tty driver
Mockern wrote: I have a question, what is really difference between serial and tty drivers? As I understand tty is high level and communicates with user space. That's pretty much it, yes. When you're talking to a serial port, you have a stack that looks roughly like: (Userspace) VFS layer tty layer --\ serial core layerline discipline serial driver (Hardware) There are other devices which can exist below the tty layer, like the pty driver: (Userspace) VFS layer tty layer --\ pty driver line discipline -hpa - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: serial and tty driver
On Sat, Feb 17, 2007 at 12:24:22PM -0600, Paul Fulghum wrote: Mockern wrote: I have a question, what is really difference between serial and tty drivers? As I understand tty is high level and communicates with user space. The serial core implements many of the details of a tty driver in a common place so that individual hardware drivers (serial drivers) only need implement the hardware specific code. This prevents duplicating tty logic in many drivers, with the possibility of mistakes/inconsistency in the different tty drivers. The stand alone tty drivers are mostly legacy code from the time before serial core that have not been ported to be a serial drivers. Not necessarily; there are a number of tty drivers, such as the console drivers and pseudo-tty drivers that have absolutely nothing to do with an RS-232 port. On the other side of the argument, another factorization of the layers that might have made sense was to move the functionality to the high-level tty layer (or in the case of hangup code, all the way up to the VFS layer as a generic sys_revoke functionality), but the reason why it didn't is largely historical. - Ted - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
