kgdb,8250,pl011: Return immediately from console poll
The design of the kdb shell requires that every device that can
provide input to kdb have a polling routine that exits immediately if
there is no character available. This is required in order to get the
page scrolling mechanism working.
Changing the kernel debugger I/O API to require all polling character
routines to exit immediately if there is no data allows the kernel
debugger to process multiple input channels.
NO_POLL_CHAR will be the return code to the polling routine when ever
there is no character available.
CC: linux-serial@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 6e1fa82..1d71df6 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -882,6 +882,8 @@
int dbg_io_get_char(void)
{
int ret = dbg_io_ops->read_char();
+ if (ret == NO_POLL_CHAR)
+ return -1;
if (!dbg_kdb_mode)
return ret;
if (ret == 127)