On Gwe, 2004-10-01 at 17:24, Al Borchers wrote:
> Its a design decision for the tty layer. You should choose whatever is
> best there and the drivers will have to adapt.
>From a tty layer I don't think there is a motivation to enforce no
sleep. Hopefully nobody has a reason to need to fiddle with termios
data in their IRQ handlers ?
> To correctly support TCSETAW/TCSETSW the USB serial drivers would have to
> have two different versions of set_termios--a non sleeping one to be called
Providing the driver isnt sticking its nose into ->ioctl the tty layer
core already correctly handles TCSETAW for you because it uses
tty_wait_until_sent before issuing the change. You don't have to deal
with that providing you've implemented driver->chars_in_buffer, and
if neccessary ->wait_until_sent.
In a waiting case the driver will get
->chars_in_buffer
until it returns zero
->wait_until_sent
->change_termios
which serializes with respect to the one writer. If you have a writer
during a termios change by another well tough luck, you lose and I've
no intention of changing that behaviour unless someone cites a standard
requiring it.
-------------------------------------------------------
This SF.net email is sponsored by: IT Product Guide on ITManagersJournal
Use IT products in your business? Tell us what you think of them. Give us
Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more
http://productguide.itmanagersjournal.com/guidepromo.tmpl
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
