Re: Seg fault on any FB write (Epson S1D13A04 on Coldfire running 2.6.25)

[Hinko Kocevar <hinko.kocevar@cetrtapot.si>]

James Kimble wrote:
> I've been working on porting the s1d13xxxfb driver from the latest 
> kernel from Freescale for Coldfire to work with the S1D13A04 chip. I was 
> able to get things working to the point that I do get a little TUX logo 
> up on the screen at boot up. Seemed like a good start but none of my 
> user space applications will work. I can open the /dev/fb0 device and 
> the data in the info structure is correct but if I try to write to any 
> register or area in the frame buffer (or write to the device at all) I 
> get a seg fault.
> 
> I had an earlier driver working with the 2.6.10 kernel with the same 
> hardware. The same application space program should work ( I would 
> think...) but I get the seg fault on the first write to fb0. I tried a 
> different memory location (ox4400 0000 to 0x7400 0000) for the CS 
> associated with the video  chip, no  difference. Permissions for 
> /dev/fb0 are "rw". No other process using fb0. This is really weird.
> 
> Any help or suggestions MUCH appreciated.
> 

You are probably not reserving and/or translating physical memory space
to virtual if you get a segfault on every access. Try cat /proc/iomem. Is
your device listed?

OTOH, a lot of arch specific code has probably changed since 2.6.10 -
2.6.25 that might not even be directly related to fb. Is your arch port
up to date?

Also you might post your fb driver and someone might spot the fault faster..


HTH,
HK
-- 
Hinko Kočevar, OSS developer
ČETRTA POT, d.o.o.
Planina 3, 4000 Kranj, SI EU
tel     ++386 (0) 4 280 66 03
e-mail  hinko.kocevar@cetrtapot.si
http    www.cetrtapot.si


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