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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [AMD Fusion E-350] HDMI refresh rates doesn't match expectations"
href="https://bugs.freedesktop.org/show_bug.cgi?id=76564#c21">Comment # 21</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [AMD Fusion E-350] HDMI refresh rates doesn't match expectations"
href="https://bugs.freedesktop.org/show_bug.cgi?id=76564">bug 76564</a>
from <span class="vcard"><a class="email" href="mailto:agd5f@yahoo.com" title="Alex Deucher <agd5f@yahoo.com>"> <span class="fn">Alex Deucher</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=76564#c20">comment #20</a>)
<span class="quote">>
> When I look at the xrandr output I wonder if the reference frequency is not
> 75MHz for fgrlx? Can the reference even change is this not fixed by the
> hardware?</span >
As far as I know, it's fixed. I'm not really sure what fglrx is doing.
Anyway, it's probably easier to just fix the open source driver.
the modes are:
1920x1080 (0x55) 148.5MHz +HSync +VSync *current +preferred
h: width 1920 start 2448 end 2492 total 2640 skew 0 clock 56.2KHz
v: height 1080 start 1084 end 1089 total 1125 clock 50.0Hz
1920x1080 (0x5a) 74.2MHz +HSync +VSync
h: width 1920 start 2558 end 2602 total 2750 skew 0 clock 27.0KHz
v: height 1080 start 1084 end 1089 total 1125 clock 24.0Hz
and the driver ends up calculating the dividers as such:
for 148.5MHz target clock:
(100Mhz * 23.8) / (2 * 8) = 148.75Mhz
for 74.2MHz target clock:
(100Mhz * 23.7) / (2 * 16) = 74.0625Mhz
One would need to tweak radeon_compute_pll_avivo() in radeon_display.c to try
and get dividers that are closer to the target clock.</pre>
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