[ipxe-devel] [PATCH] [efi] Fix console driver's iskey

[tong ho]

Problem Description

iPXE calls a console driver's iskey entry two or more times without
calling the getchar entry in between.  This usage is not consistent
with the CheckEvent uEFI service, which clears the keystroke event
per uEFI spec.  The clearing side-effect leads to false-negative
result from iskey() when it is called two or more times without
an intervening call to getchar.  The false-negative result causes
iPXE to discard every other keystroke.

Solution

This patch changes iskey() to probe for outstanding keystroke by
calling getchar().  If a keystroke is found, it is placed in the
driver's buffer for later return, by extending the current scheme
for returning ansi escape sequences.

Thanks.

Regard,
Tong Ho
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