Re: LCD_Backlight

Hello voidcoder,

I am using the standard wince5.0 full power management.It is in the PM
module(in Public root)
it reads the name and timeout from the registry and is handling the same I
am acessing the same events in my backlight driver. Also the document on
"Activity timers" says that the PM module opens 3 events :
PowerManager/ActivityTimer/SystemActivity (Auto reset event)
PowerManager/SystemActivity_Active, and
PowerManager/SystemActivity_Inactive (both manual reset event)
The document also states
Any number of threads may open handles to the manual-reset
activity/inactivity events and wait on them to determine the status of the
OS. For example, a backlight driver may use the pair of manual-reset events
created for an activity timer to decide how to control backlight power and
intensity.
This is the reason why I am waiting on the two events. Now as per my
requirement when i touch the screen or on some other activity if i want the
back light to be ON I need to set this event ie tell the system that The
system is active and keep the backlight on for another period of time.I am
doing the same via SetEvent() which does not seem to set my activity event.
I went through your code and am unable to understand which of
this is a auto reset and which is a manual reset event. In manual reset i
need to manually reset the event(which i am trying to do in my backlight
driver). I fail to understand that if my thread is waiting for the active
event and i set it throught the touch why does'nt it reflect??


Now this is the reason why I have open handles to these events and am
waiting on them



"voidcoder" wrote:

I do not understand why do you need TWO thread to
wait on ativity timers. One is just enough, see my
example. Also not clear why do you need to reset
events in your touch driver? This is done automatically
as part of windows input handling.

Btw why do you need SystemActivity? Isn't the
!UserActivity! what are you looking for?


"Anurag" <Anurag@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message news:49CEEE5B-3009-4372-9DC2-32CD4D485BDE@xxxxxxxxxxxxxxxx
Hello voidcoder,
This are my registry settings:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\ActivityTimers\SystemActivity]
"Timeout"=dword:A

In my backlight driver Init function I create two events with thier names
the return value is the handle to the existing events:
if((SysAct_Active = CreateEvent(NULL, FALSE,
FALSE,_T("PowerManager/SystemActivity_Active")))!= NULL)
{
if(ERROR_ALREADY_EXISTS == GetLastError())
NKDbgPrintfW(TEXT(" ERROR_ALREADY_EXISTS 1\r\n"));
else
NKDbgPrintfW(TEXT(" Event created 1 %d \r\n"),SysAct_Active);

}
else
NKDbgPrintfW(TEXT("Event not created 1\r\n"));

if((SysAct_Inactive = CreateEvent(NULL, FALSE,
FALSE,_T("PowerManager/SystemActivity_Inactive"))) != NULL)
{
if(ERROR_ALREADY_EXISTS == GetLastError())
NKDbgPrintfW(TEXT(" ERROR_ALREADY_EXISTS 2\r\n"));
else
NKDbgPrintfW(TEXT(" Event created 2 %d\r\n"),SysAct_Inactive);

}
else
NKDbgPrintfW(TEXT("Event not created 2 %d\r\n"));

// i create two threads
hThread1 = CreateThread( NULL, 0, System_Active, 0, 0, NULL); // thread
created as active
hThread2 = CreateThread( NULL, 0, System_Inactive, 0, CREATE_SUSPENDED,
NULL);// thread
//created in suspended state
NKDbgPrintfW(TEXT(" Both Threads created\r\n"));

the two threads are as follows:

static ULONG
System_Active(
PVOID Reserved
)
{

WaitForSingleObject( SysAct_Active, INFINITE );
NKDbgPrintfW(TEXT(" out of WaitForSingleObject:SystemActivity_Active\r\n"));
Signal_BKL(1); //control back_light
if(ResetEvent(SysAct_Active))
NKDbgPrintfW(TEXT("ASA : SysAct_Active Event reset\r\n"));
else
NKDbgPrintfW(TEXT("ASA : SysAct_Active Event could not reset\r\n"));

ResumeThread(hThread2);
SuspendThread(hThread1);
return(TRUE);
}


static ULONG
System_Inactive(
PVOID Reserved
)
{
WaitForSingleObject( SysAct_Inactive, INFINITE );
NKDbgPrintfW(TEXT(" out of WaitForSingleObject:SystemInactivity_Active
\r\n"));
Signal_BKL(0); //control back_light
if(ResetEvent(SysAct_Inactive))
NKDbgPrintfW(TEXT("ASA : SysAct_Inactive Event reset\r\n"));
else
NKDbgPrintfW(TEXT("ASA : SysAct_Inactive Event could not reset\r\n"));

ResumeThread(hThread1);
SuspendThread(hThread2);
return(TRUE);
}


In the touch driver MDD main.c I first open the handle to the event

if((SysAct_Reset =
OpenEvent(EVENT_ALL_ACCESS,FALSE,_T("PowerManager/SystemActivity_Active")))!=
NULL)
{
if(ERROR_ALREADY_EXISTS == GetLastError())
NKDbgPrintfW(TEXT(" ERROR_ALREADY_EXISTS 3\r\n"));
else
NKDbgPrintfW(TEXT("Reset Event created again %d \r\n"),SysAct_Reset);

}
else
NKDbgPrintfW(TEXT("Event not created 1\r\n"));

then in the touch IST i try to set the event

if(SetEvent(SysAct_Reset))
NKDbgPrintfW(TEXT("ASA:Reset event set\r\n"));
else
NKDbgPrintfW(TEXT("ASA:Reset event NOT set\r\n"));


when i touch the screen it does not set the activity timer event and my
backlight does not switch on.
I would certainly appreciate your valuable help over this.

Thankyou


"voidcoder" wrote:

Ops, typo in my prev post:


DWORD dwBacklightTimeout = ReadTimeoutFromRegistry(...);

while (TRUE)
{
WaitForSingleObject(hInactivityTimer, INFINITE);

if (WaitForSingleObject(hActivityTimer, dwBacklightTimeout) ==
WAIT_TIMEOUT)
{
TurnBacklightOff();
WaitForSingleObject(hActivityTimer, INFINITE);
TurnBacklightOn();
}
}




"voidcoder" <voidcoder@xxxxxxxxx> wrote in message news:ewg0qm2ZGHA.1560@xxxxxxxxxxxxxxxxxxxxxxx

I'm not sure what are you doing there. Post you code.

Have not used activity timers this way, but it should
be possible to use something like this:


DWORD dwBacklightTimeout = ReadTimeoutFromRegistry(...);

while (TRUE)
{
WaitForSingleObject(hInactivityTimer, INFINITE);

if (WaitForSingleObject(hActivityTimer, dwBacklightTimeout) ==
WAIT_OBJECT_0)
{
TurnBacklightOff();
WaitForSingleObject(hActivityTimer, INFINITE);
TurnBacklightOn();
}
}




"Anurag" <Anurag@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:4810CF02-46E0-435B-9E63-BC98D849FEF9@xxxxxxxxxxxxxxxx
Hello Voidcoder,
Thankyou for reply !!!!
Actually I am able to acess the events in my backlight driver ie it does set
the activity event("PowerManager/SystemActivity_Active") during boot then
after 10 sec(set in registry) it sets the inactivity event
("PowerManager/SystemActivity_Inactive") and I am able to acknowledge it in
my backlight driver. I am trying to set the activity event in my touch driver
so that every time i touch the screen the activity event is set and the the
activity timer count initializes. Now this does not happen!! I am setting the
event as follows:
if(SetEvent(SysAct_Reset))
NKDbgPrintfW(TEXT("ASA:Reset event set\r\n"));

Note: SysAct_Reset is the handle to
"PowerManager/ActivityTimer/SystemActivity" event

what happens is that once the inactivity event is set the light goes off and
does not resume back. I am resetting the manual reset inactivity event
("PowerManager/SystemActivity_Inactive") by reset event.
What could be the issue ??? In anticipation of your reply ASAP.

"voidcoder" wrote:

Actually activity timers are named as follow:

PowerManager/ActivityTimer/$Activity$
PowerManager/$Activity$_Active
PowerManager/$Activity$_Inactive

Eg.

"PowerManager/ActivityTimer/SystemActivity"
"PowerManager/SystemActivity_Active"
"PowerManager/SystemActivity_Inactive"

Use OpenEvent() to access events.


"Anurag" <Anurag@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:A2F1D358-DE0B-4FC6-B084-D283DAADF6F2@xxxxxxxxxxxxxxxx
Hello Voidcoder,
Thankyou for your reply .
certainly setting the power states would be much better however for the
purpose of curiosity I tried adding that registry entry
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\ActivityTimers\SystemActivity]
"Timeout"=dword:A

and then created the events with the same names i.e, SystemActivity_Active
&
SystemActivity_Inactive in my driver however these events get created. Now
according to WinCE documentation (wince help topic Activitytimers) Upon
initialization, the Power Manager reads the registry to acquire a list of
activity timer names and creates the following events:
A timer reset event.
An active status manual-reset event.
A manual-reset event.

hence when i create the events with thier names Createevent() should
return
ERROR_ALREADY_EXISTS however this doesn't happen the events get created.
why is it so????
What needs to be done in this case??

"Voidcoder" wrote:

I would advice to not touch the system activity
timer directly. Better build a simple driver and
handle the power IOCTLs. You will need to
handle IOCTL_POWER_SET ioctl this way:

IOCTL_POWER_SET - D0 -> turn backlight on
IOCTL_POWER_SET - D1 -> turn backlight off


"Anurag" <Anurag@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:ADEEAC32-2DCE-4ABF-B45C-E83EC1BE1D1F@xxxxxxxxxxxxxxxx
Hello everybody,
I am trying to develop a screen saver like facility for my WINCE Image
i.e,
after a predifined time of inactivity the LCD backlight should be OFF
and
on some activity like a touch on the touchscren the backlight should
get ON
I reffered the wince documentation "activity timer "and find that
activity
timers can be used i.e, set an activity timer
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\ActivityTimers\SystemActivity]
"Timeout"=dword:A
"WakeSources"=multi_sz:"0x20"


and the power manager handles the events.. Also the event can be
handled via
driver. In my case I am using the wince full power management as it is.
I am
a bit confused on the overall working as to how do i open a handle to
the
reset event in a driver? once the timeout is done how do i turn off my
backlight?
In my target the backlight is located on a gpio and can be controlled
via it
. Should i create a bcklight driver? if yes how to call the driver
once the
timeout is done.
I would be highly obliged to recieve your guidance
regarding
the same
Thankyou.

Ansh














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