2014-12-09 21:33:50

by Ondrej Zary

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Subject: Compiled tridentfb hangs but distribution kernel works fine

Hello,
I'm doing some work on tridentfb driver but encountered a weird problem.

When I compile custom kernel with tridentfb, it hangs with Blade3D card (ID
0x9880) in blade_image_blit(). The screen is blank with some artifacts and
machine does not respond to ping or keyboard. However, it can be rebooted by
Alt+SysRq+B. It works fine with other cards (3DImage 9750 and CyberBlade XP)
with no blit implementation. Commenting out contents of blade_image_blit()
function makes the hang go away (nothing useful on the screen, of course).

The weird thing is that the Blade3D card works fine when I load Debian
kernels! Debian 3.16-0.bpo.3-686-pae works fine but when I compile 3.16
kernel, it hangs.

Any ideas?


--
Ondrej Zary


2014-12-10 07:15:12

by Mike Galbraith

[permalink] [raw]
Subject: Re: Compiled tridentfb hangs but distribution kernel works fine

On Tue, 2014-12-09 at 22:33 +0100, Ondrej Zary wrote:
> Hello,
> I'm doing some work on tridentfb driver but encountered a weird problem.
>
> When I compile custom kernel with tridentfb, it hangs with Blade3D card (ID
> 0x9880) in blade_image_blit(). The screen is blank with some artifacts and
> machine does not respond to ping or keyboard. However, it can be rebooted by
> Alt+SysRq+B. It works fine with other cards (3DImage 9750 and CyberBlade XP)
> with no blit implementation. Commenting out contents of blade_image_blit()
> function makes the hang go away (nothing useful on the screen, of course).
>
> The weird thing is that the Blade3D card works fine when I load Debian
> kernels! Debian 3.16-0.bpo.3-686-pae works fine but when I compile 3.16
> kernel, it hangs.
>
> Any ideas?

I'd start by looking for what Debian changed in source and/or config.

-Mike

2014-12-11 23:08:24

by Ondrej Zary

[permalink] [raw]
Subject: Re: Compiled tridentfb hangs but distribution kernel works fine

On Wednesday 10 December 2014 08:15:04 Mike Galbraith wrote:
> On Tue, 2014-12-09 at 22:33 +0100, Ondrej Zary wrote:
> > Hello,
> > I'm doing some work on tridentfb driver but encountered a weird problem.
> >
> > When I compile custom kernel with tridentfb, it hangs with Blade3D card
> > (ID 0x9880) in blade_image_blit(). The screen is blank with some
> > artifacts and machine does not respond to ping or keyboard. However, it
> > can be rebooted by Alt+SysRq+B. It works fine with other cards (3DImage
> > 9750 and CyberBlade XP) with no blit implementation. Commenting out
> > contents of blade_image_blit() function makes the hang go away (nothing
> > useful on the screen, of course).
> >
> > The weird thing is that the Blade3D card works fine when I load Debian
> > kernels! Debian 3.16-0.bpo.3-686-pae works fine but when I compile 3.16
> > kernel, it hangs.
> >
> > Any ideas?
>
> I'd start by looking for what Debian changed in source and/or config.

Seems that the problem appears only of CONFIG_CC_OPTIMIZE_FOR_SIZE is enabled.
Really weird.

--
Ondrej Zary