[Bug 76564] [AMD Fusion E-350] HDMI refresh rates doesn't match expectations

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=76564

--- Comment #14 from Alex Deucher <agd5f at yahoo.com> ---
(In reply to comment #13)
> Do the PLL values in the log files I posted indicate a problem, or are they
> okay?

[drm:radeon_compute_pll_avivo], 14875, pll dividers - fb: 23.8 ref: 2, post 8
[drm:radeon_compute_pll_avivo], 7406, pll dividers - fb: 23.7 ref: 2, post 16

The display pll looks fine to me. The clock formula is:

pixel_clock = (reference_frequency * feedback_divider) / (reference_divider *
post_divider)

The reference frequency is 100 Mhz, so:

(100Mhz * 23.8) / (2 * 8) = 148.75Mhz

(100Mhz * 23.7) / (2 * 16) = 74.0625Mhz

> 
> How can you see the PLL values fglrx is using?

You'd need to dump the PLL registers using radeonreg
(http://cgit.freedesktop.org/~airlied/radeontool/).
PPLL1
0x400 - ref div - bits 9:0
0x404 - fb div - whole part bits 26:16, fractional part bits 3:0
0x408 - post div - bits 6:0
PPLL2
0x440 - ref div - bits 9:0
0x444 - fb div - whole part bits 26:16, fractional part bits 3:0
0x448 - post div - bits 6:0

e.g., ./radeonreg regmatch 0x400

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