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javispedro's Avatar
Posts: 2,355 | Thanked: 5,249 times | Joined on Jan 2009 @ Barcelona
#1
I found the reason why recent N900 firmwares don't like GVM. GVM seems to issue a cacheflush syscall via OABI (aka swi $1 with $1 != 0) from time to time while running ARMlets, and I just noticed that the latest N900 kernel doesn't have CONFIG_OABI_COMPAT.

Enabling CONFIG_OABI_COMPAT in kernel build config causes GVM to work again like on the N8x0.

Sorry for not providing a fix (but should be easy enough to fix if you're using a patched/"community" kernel). I think I'll email GVM about this to see if they can fix it in the next version.
 
BrentDC's Avatar
Posts: 903 | Thanked: 632 times | Joined on Apr 2008
#2
I've been having a lot of trouble getting some programs to work in the GVM on my N900 that had worked on my N800.

Most notably, The Quest by Redshift. It was not very usable on the N800 because it was very graphic-intensive and slow, but with the N900's upgraded hardware I was hoping for better results.

However, the program does not run (crashes on startup). Doesn't matter how much memory I give it, it still crashes. I've noticed this with many of the more advanced Palm programs (for OS 5+), while OS 3.5 programs seem to work fine.

Do you think that it is some system call by newer Palm programs that is unavailable which is causing this problem? I know, a shot in the dark...

Sorry if this is way off-topic!
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-Brent

Author of TouchSearch -- web searching software for Maemo 5.

Mobile Device lineage: Palm Z22 -> Palm TX -> Nokia N800 -> Nokia N900
 
javispedro's Avatar
Posts: 2,355 | Thanked: 5,249 times | Joined on Jan 2009 @ Barcelona
#3
Originally Posted by BrentDC View Post
Doesn't matter how much memory I give it, it still crashes. I've noticed this with many of the more advanced Palm programs (for OS 5+), while OS 3.5 programs seem to work fine.
Actually this is completely on topic, as this is exactly the issue I'm experiencing; most "OS5+ only" programs contain ARMlets/PNOlets, and as I explain on my post, they fail to work on the N900 because of the OABI cacheflush call.

Solutions:
A ) ACCESS should be able to easily fix/workaround this, so poke them. I already sent them the above using their feedback form .
B) Use a kernel with CONFIG_OABI_COMPAT=y. I can build it (zImage only), but won't provide support for it, so better ask titan or somebody who will.
C) Binary patch GVM. Ugly, and hard .

And yes, performance of armlets seems improved on N900, as I get nearly 30% more frames per second on my PalmGL port.

Last edited by javispedro; 2010-05-15 at 16:06.
 
Posts: 87 | Thanked: 13 times | Joined on Dec 2009
#4
Perhaps we should ask titan then, As ACCESS will probably never update their GVM...

I really would like to have Mobipocket and iSilo work properly again... Perhaps this will fix it.
 
javispedro's Avatar
Posts: 2,355 | Thanked: 5,249 times | Joined on Jan 2009 @ Barcelona
#5
Originally Posted by mtjioe View Post
As ACCESS will probably never update their GVM...
I used to say this but they have been regularly updating it -- in fact you should expect next update this month.
 
Posts: 87 | Thanked: 13 times | Joined on Dec 2009
#6
OK, lets wait and see....

Last edited by mtjioe; 2010-08-05 at 05:48.
 
BrentDC's Avatar
Posts: 903 | Thanked: 632 times | Joined on Apr 2008
#7
Originally Posted by javispedro View Post
Actually this is completely on topic, as this is exactly the issue I'm experiencing; most "OS5+ only" programs contain ARMlets/PNOlets, and as I explain on my post, they fail to work on the N900 because of the OABI cacheflush call.

Solutions:
A ) ACCESS should be able to easily fix/workaround this, so poke them. I already sent them the above using their feedback form .
B) Use a kernel with CONFIG_OABI_COMPAT=y. I can build it (zImage only), but won't provide support for it, so better ask titan or somebody who will.
C) Binary patch GVM. Ugly, and hard .

And yes, performance of armlets seems improved on N900, as I get nearly 30% more frames per second on my PalmGL port.
I haven't followed much of the kernel modding stuff, but this sounds promising! Are you planning on releasing a flashable version of the kernel with that flag set? If you did, I would certainly try it out.
__________________
-Brent

Author of TouchSearch -- web searching software for Maemo 5.

Mobile Device lineage: Palm Z22 -> Palm TX -> Nokia N800 -> Nokia N900
 
javispedro's Avatar
Posts: 2,355 | Thanked: 5,249 times | Joined on Jan 2009 @ Barcelona
#8
I uploaded a zImage with oabi compatibility enabled here: zImage-n900-oabi-compat. Note though that it is the SDK PR1.2 version of the kernel, thus I'm not sure if I'd use it for daily operation.

You need flasher or flasher-3.5 to load or flash it.
 
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