nanogui: Framebuffer driver Epson LCD controller
Subject:
Framebuffer driver Epson LCD controller
From:
"Mads leMaire" ####@####.####
Date:
16 Jan 2001 09:08:27 -0000
Message-Id: <sa641e79.067@jotron.com>
Hi!
I am currently writing a linux framebufferdriver for the EPSON SED1375 LCD controller connected to the PC hardware through the ISA bus. I can easily map the display memory and the control registers (which are memory mapped as the display memory) into both the kernel driver and my microwindows user program. However, update of the lookuptable is special on this controller. You can setup a pointer to a RGB entry in the table (0-255) and then write consecutive RGB values into another register. The controller is then internally autoincrementing the pointer to where the entries will arrive in the lookup table. The strange thing (to me) is that this works fine using the mmapped pointer in the application, but it does not work when executed from the kernel driver! Can the memory cycles on the ISA bus be different in user/kernel mode?
Anyone experienced something like this?
regards
Mads Olav le Maire
