/usr/bin/brcm_patchram_plus chews 100% cpu on nexus 7

[James Hunt]

Ubuntu Saucy Salamander (development branch) - armhf (20130822)
nexus 7 (grouper)

brcm_patchram_plus is spinning at 100% cpu

$ ps -ef|grep brcm
root 475 1 0 09:36 ? 00:00:00 /usr/bin/brcm_patchram_plus --patchram /system/etc/firmware/bcm4330.hcd --no2bytes --scopcm=0,2,0,0,0,0,0,0,0,0 --enable_hci --enable_lpm --baudrate 3000000 --use_baudrate_for_download --tosleep=50000 /dev/ttyHS2
1002 518 464 99 09:36 ? 03:02:25 /system/bin/brcm_patchram_plus --enable_hci --scopcm=0,2,0,0,0,0,0,0,0,0 --baudrate 3000000 --use_baudrate_for_download --patchram /etc/firmware/bcm4330.hcd --no2bytes --enable_lpm --tosleep=50000 /dev/ttyHS2

strace shows a continual stream of read calls:

read(8, "", 3) = 0
read(8, "", 3) = 0
read(8, "", 3) = 0
read(8, "", 3) = 0
read(8, "", 3) = 0
read(8, "", 3) = 0
read(8, "", 3) = 0

[James Hunt (jamesodhunt)]

Its trying to read from /dev/ttyHS2:

phablet@ubuntu-phablet:~$ sudo ls -l /proc/518/fd
total 0
lrwx------ 1 1002 bluetooth 64 Aug 28 12:40 0 -> /dev/null
lrwx------ 1 1002 bluetooth 64 Aug 28 12:40 1 -> /dev/null
lrwx------ 1 1002 bluetooth 64 Aug 28 12:40 2 -> /dev/null
l-wx------ 1 1002 bluetooth 64 Aug 28 12:40 3 -> /dev/alog/main
l-wx------ 1 1002 bluetooth 64 Aug 28 12:40 4 -> /dev/alog/radio
l-wx------ 1 1002 bluetooth 64 Aug 28 12:40 5 -> /dev/alog/events
l-wx------ 1 1002 bluetooth 64 Aug 28 12:40 6 -> /dev/alog/system
lr-x------ 1 1002 bluetooth 64 Aug 28 12:40 7 -> /system/etc/firmware/bcm4330.hcd
lrwx------ 1 1002 bluetooth 64 Aug 28 12:40 8 -> /dev/ttyHS2
lr-x------ 1 1002 bluetooth 64 Aug 28 12:40 9 -> /dev/__properties__ (deleted)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.