[Bug 69723] Computer freezes with kernel 3.11.0 / 3.12-rc1 (with bug 68235's patches applied) when dpm=1 on r600g (Cayman)

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=69723

--- Comment #27 from Alexandre Demers <alexandre.f.demers at gmail.com> ---
(In reply to comment #26)
> Alex, in drivers/gpu/drm/radeon/ni_dpm.c, when we are limiting the sclk and
> mclk to the max speed according to vddc and vddci, aren't we screwing
> possibly something with mclk? I mean, could we be setting a mclk value that
> is wrong? We have two conditions where we can max mclk value, but we are not
> looking at the lowest one. I think it should be something like this instead
> to be sure we are using the most restrictive value:
> 	/* Select the lowest mclk value according to the most restrictive between
> vddc and vddci*/
> 	if (max_mclk_vddc || max_mclk_vddci) {
> 		max_mclk_vddcx = (max_mclk_vddc > max_mclk_vddci) ? max_mclk_vddci :
> max_mclk_vddc;
> 	}
> 
> 	for (i = 0; i < ps->performance_level_count; i++) {
> 		if (max_sclk_vddc) {
> 			if (ps->performance_levels[i].sclk > max_sclk_vddc)
> 				ps->performance_levels[i].sclk = max_sclk_vddc;
> 		}
> 		if (max_mclk_vddcx) {
> 			if (ps->performance_levels[i].mclk > max_mclk_vddcx)
> 				ps->performance_levels[i].mclk = max_mclk_vddcx;
> 		}
> 	}
> 
> I'm also quoting you: "Not exactly. Mclk is tied to vddci (memory interface
> voltage), but both mclk and sclk (and the core display clock) are tied to
> vddc (core voltage)." Which means, mclk shouldn't run at its max speed if
> vddc is not at its max value, isn't it? Otherwise, we may encounter
> stability problem.

Forget this, I'm getting tired and I didn't realized that we were already
making sure we were maxing the value if it was smaller.

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