Epson S1D13705 technical manual Vancouver Design Center

Page 14	Epson Research and Development
	Vancouver Design Center

•Since display data is not saved and not repainted, this is the FASTEST mode.

•Main display data in display memory must NOT be corrupted or lost on sus- pend. The memory clock must remain running.

•Off-screen data in display memory must NOT be corrupted or lost on sus- pend. The memory clock must remain running.

•This mode cannot be used if power to the display memory is turned off.

b.PORepaint=1

•This is the default mode for Windows CE.

•This mode tells Windows CE to save the main display data to the system memory on suspend.

•This mode is used if display memory power is going to be turned off when the system is suspended, and there is enough system memory to save the image.

•Any off-screen data in display memory is LOST when suspended. Therefore off-screen memory usage must either be disabled in the display driver (i.e: EnablePreferVmem not defined in SOURCES file), or new OEM-specific code must be added to the display driver to save off-screen data to system memory when the system is suspended, and restored when resumed.

•If off-screen data is used (provided that the OEM has provided code to save off-screen data when the system suspends), additional code must be added to the display driver’s surface allocation routine to prevent the display driver from allocating the “main memory save region” in display memory. When WinCE OS attempts to allocate a buffer to save the main display data, WinCE OS marks the allocation request as preferring display memory. We believe this is incorrect. Code must be added to prevent this specific allocation from being allocated in display memory - it MUST be allocated from system mem- ory.

•Since the main display data is copied to system memory on suspend, and then simply copied back on resume, this mode is FAST, but not as fast as mode 0.

c.PORepaint=2

•This mode tells WinCE to not save the main display data on suspend, and causes WinCE to REPAINT the main display on resume.

•This mode is used if display memory power is going to be turned off when the system is suspended, and there is not enough system memory to save the im- age.

•Any off-screen data in display memory is LOST, and since there is insuffi- cient system memory to save display data, off-screen memory usage MUST be disabled.

•When the system is resumed, WinCE instructs all running applications to re- paint themselves. This is the SLOWEST of the three modes.

S1D13705	Windows® CE 3.x Display Drivers
X27A-E-006-01	Issue Date: 01/05/25