In below calling stack:
UsbBootIsUnitReady()
UsbBootExecCmdWithRetry()
UsbBootExecCmd()
UsbBootRequestSense()
When USB CDROM is hot-plugged, UsbBootRequestSense() retrieves sense
key (6 = UnitAttention), additional sense code (29h = Power ON).
But it wrongly maps such sense data to Device Error status.
It causes UsbBootExecCmd() executed again.
In the second time call to UsbBootExecCmd(), UsbBootRequestSense()
retrieves sense key (6 = UnitAttention), additional sense code
(28h = media changed).
The above analysis explains why hot-plug USB CDROM cannot be
recognized after below commit:
SHA1 a662afb5b0
* MdeModulePkg/UsbStorage: Fix "map -r" cannot detect media change,
which removes the media changed status check in UsbBootDetectMedia().
The proper fix to this problem is to map the ASC (additional sense
code 29h) properly to success status so that no second call to
UsbBootExecCmd() is made.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
The majority of the content in the EDK II open source project uses a
BSD 2-Clause License. The EDK II open source project contains
the following components that are covered by additional licenses:
6461344c31