Re: [PATCH] tty: Fix tcdrain hang due to tty chars_in_buffer errors

[Alan Cox]

On Fri, 17 Jul 2009 11:07:54 -0400
Jeff Harris <jeff_harris@xxxxxxxxxxx> wrote:

> If a tty driver's chars_in_buffer callback reports an error, the wait loop in

chars_in_buffer cannot report an error. It reports how many characters
are in the buffer.

> A process calling tcdrain will block indefinitely if it calls tcdrain when the
> device is disconnected.

Fix your chars_in_buffer. On a disconnect its quite reasonable to return
0, as they are not buffered any more.

Alan
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