<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <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#c28">Comment # 28</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 <a class="email" href="mailto:jeroenk61@hotmail.com" title="jeroen <jeroenk61@hotmail.com>"> jeroen</a> <pre>(In reply to <a href="show_bug.cgi?id=76564#c27">comment #27</a>) > (In reply to <a href="show_bug.cgi?id=76564#c26">comment #26</a>) > > (In reply to <a href="show_bug.cgi?id=76564#c25">comment #25</a>) > > > (In reply to <a href="show_bug.cgi?id=76564#c24">comment #24</a>) > > > > (In reply to <a href="show_bug.cgi?id=76564#c23">comment #23</a>) > > > > The problem is that the frequencys are exact enough so that the display > > > > device (Monitor/TV/Whatever) accepts them, but not 100% precise. > > > > > > > > E.g. for the 50Hz mode we wanted 148.5MHz pixel clock, but got 148.75Mhz > > > > instead. And for the 24Hz mode we wanted 74.2MHz but got 74.0625Mhz instead. > > > > > > > > So as Alex said somebody would need to dig into that and try to improve the > > > > numbers without toasting the hardware. > > > > > > So that would mean for example using fb=29.7 Ref=2 post=10? > > > > > > Or would that fry the hardware? > > > > That should work. You aren't likely to fry the hw. You just don't want to > > set a 400 Mhz clock as you monitor properly won't like it. The hard part is > > adjusting the algorithm to reliably calculate a good value for a wide range > > of clocks. > > I'm not sure if those values would work. A post divider of 10 might result > in a to high VCO and that could indeed damage the hardware (even if that's > rather unlikely). > > Essentially the target clock multiplied with the post divider must be in a > certain range. I think between pll->pll_out_max and pll->pll_out_min. > > I think the problem is that we don't try to choose a good value to match the > target frequency as close as possible in avivo_get_post_div, but just a > value that either matches the maximum or minimum VCO frequency. Perhaps before somebody is going to modify the algorithm, it is a good idea to verify that this is indeed the problem. If this is the problem why don't more people have these problems? If I know which values for fb,ref and post to use for 23.976fps I can hard code these In a patch and test if it indeed works. So which values are save to get a clock of 74.2MHz?</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>