the software cursor starts flickering and reacts bumby if a process
spends most of its time with drawlock acquired because the timer interrupt
thats supposed to redraw the cursor fails to acquire the lock at the time
the timer fires.
instead of trying to draw the cursor on the screen from a timer interrupt
30 times per second, devmouse now creates a process calling cursoron() and
cursoroff() when the cursor needs to be redrawn. this allows the swcursor
to schedule a redraw while holding the drawlock in swcursoravoid() and
cursoron()/cursoroff() are now able to wait for a qlock (drawlock) because
they get called from process context.
the overall responsiveness is also improved with this change as the cursor
redraw rate isnt limited to 30 times a second anymore.
from ehci spec:
The buffer pointer list in the qTD is long enough to support a maximum
transfer size of 20K bytes. This case occurs when all five buffer pointers
are used and the first offset is zero. A qTD handles a 16Kbyte buffer
with any starting buffer alignment.
overriding aborttime in udpquery() makes no sense. it causes
recursive queries to extend the timeout infinitely. nobody
but the issuer of the request should modify aborttime.
*alen has to be initialized to the size of the buffer
by the caller, and we are supposed to put the real
size of the address in there, but not copy more than
the original *alen value (truncate).
in wpa2, the rsc field of the eapol message3 is the packet number for
*group* messages that the ap will use as there is no separate group
key message. in wpa1, we use it for the peerwise key.
the kernel uses fixed area (TSTKTOP, TSTKSIZ) of the address
space to temporarily map the new stack segment for exec. for
386 and arm, this area was right below the stack segment which
has the problem that the program can map arbitrary segments
there (even readonly).
alpha and ppc dont have this problem as they map the temporary
exec stack *above* the user reachable stack segement and segattach
prevents one from mapping anything above or overlaping the stack.
lots of arch code assumes USTKTOP being the end of userspace
address space and changing this to TSTKTOP would work, but results
in lots of hard to test changes.
instead, we'r going to map the temporary stack programmatically
finding a hole in the address space where to map it. we also lift
the size limitation for arguments and allow arguments to fill
the whole new stack segement.
the TSTKTOP and TSTKSIZ are not used anymore so they where removed.
references:
http://9fans.net/archive/2013/03/203http://9fans.net/archive/2013/03/202http://9fans.net/archive/2013/03/197http://9fans.net/archive/2013/03/195http://9fans.net/archive/2013/03/181
