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| author | Tomasz Wroblewski <tomasz.wroblewski@citrix.com> | 2013-08-28 10:19:42 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2013-08-28 10:19:42 +0200 |
| commit | 37f36d894ef43dc2986d0936612ec967c5a89be8 (patch) | |
| tree | 3294c6a581fce860ce455d0a48cf16e430c95888 /xen/include/xen | |
| parent | 9e2c5938246546a5b3f698b7421640d85602b994 (diff) | |
| download | xen-37f36d894ef43dc2986d0936612ec967c5a89be8.tar.gz xen-37f36d894ef43dc2986d0936612ec967c5a89be8.tar.bz2 xen-37f36d894ef43dc2986d0936612ec967c5a89be8.zip | |
PCI UART: better cope with UART being temporarily unavailable
This happens for example when dom0 disables ioport responses during PCI
subsystem initialisation. If a __ns16550_poll() happens to be scheduled
during that time, Xen hangs. Detect and exit that condition.
Amended ns16550_ioport_invalid function to only check IER register,
which contins 3 reserved (always 0) bits, therefore it's sufficient for
that test.
Signed-off-by: Tomasz Wroblewski <tomasz.wroblewski@citrix.com>
Acked-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'xen/include/xen')
| -rw-r--r-- | xen/include/xen/serial.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/xen/include/xen/serial.h b/xen/include/xen/serial.h index 403e193d96..f38c9b7f54 100644 --- a/xen/include/xen/serial.h +++ b/xen/include/xen/serial.h @@ -70,8 +70,9 @@ struct uart_driver { /* Driver suspend/resume. */ void (*suspend)(struct serial_port *); void (*resume)(struct serial_port *); - /* Return number of characters the port can hold for transmit. */ - unsigned int (*tx_ready)(struct serial_port *); + /* Return number of characters the port can hold for transmit, + * or -EIO if port is inaccesible */ + int (*tx_ready)(struct serial_port *); /* Put a character onto the serial line. */ void (*putc)(struct serial_port *, char); /* Flush accumulated characters. */ |