From ae030e435f5400cff77c52506a8d3d7278f0947c Mon Sep 17 00:00:00 2001 From: Paul Fulghum Date: Wed, 9 May 2007 02:33:38 -0700 Subject: [PATCH] tty_set_ldisc() receive_room fix Fix tty_set_ldisc in tty_io.c so that tty->receive_room is only cleared if actually changing line disciplines. Without this fix a problem occurs when requesting the line discipline to change to the same line discipline. In this case tty->receive_room is cleared but ldisc->open() is not called to set tty->receive_room back to a sane value. The result is that tty->receive_room is stuck at 0 preventing the tty flip buffer from passing receive data to the line discipline. For example: a switch from N_TTY to N_TTY followed by a select() call for read input results in data never being received because tty->receive_room is stuck at zero. A switch from N_TTY to N_TTY followed by a read() call works because the read() call itself sets tty->receive_room correctly (but select does not). Previously (< 2.6.18) this was not a problem because the tty flip buffer pushed data to the line discipline without regard for tty->receive room. Signed-off-by: Paul Fulghum Acked-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-format-patch failed