console/serial: bump buffer from 16K to 32K

Testing on a Kaby Lake box with 8 CPUs leads to the serial buffer
being filled halfway during dom0 boot, and thus a non-trivial chunk of
Linux boot messages are dropped.

Increasing the buffer to 32K does fix the issue and Linux boot
messages are no longer dropped.  There's no justification either on
why 16K was chosen, and hence bumping to 32K in order to cope with
current systems generating output faster does seem appropriate to have
a better user experience with the provided defaults.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>

diff --git a/xen/drivers/char/Kconfig b/xen/drivers/char/Kconfig
index 06350c38737100abcce12b97a6514c8fce714f5b..e18ec3788c715ced99ae52f2b35ee90ebba090e3 100644 (file)
--- a/xen/drivers/char/Kconfig
+++ b/xen/drivers/char/Kconfig
@@ -77,13 +77,13 @@ config HAS_EHCI
 
 config SERIAL_TX_BUFSIZE
        int "Size of the transmit serial buffer"
-       default 16384
+       default 32768
        help
          Controls the default size of the transmit buffer (in bytes) used by
          the serial driver.  Note the value provided will be rounded down to
          the nearest power of 2.
 
-         Default value is 16384 (16kiB).
+         Default value is 32768 (32KiB).
 
 config XHCI
        bool "XHCI DbC UART driver"