[Bug 97965] [BSW] External HDMI monitor suddenly shows solid color when playing Youtube video at 1080p [fifo underrun]

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=97965

--- Comment #30 from Yu Kang Ku <ykku16dev2 at gmail.com> ---
In intel_display.c, there is one difference between valleyview_set_cdclk() and
cherryview_set_cdclk() that seems rather interesting.  The following snippet is
in valleyview_set_cdclk() but NOT in cherryview_set_cdclk():

        /* adjust self-refresh exit latency value */
        val = vlv_bunit_read(dev_priv, BUNIT_REG_BISOC);
        val &= ~0x7f;

        /*
         * For high bandwidth configs, we set a higher latency in the bunit
         * so that the core display fetch happens in time to avoid underruns.
         */
        if (cdclk == 400000)
                val |= 4500 / 250; /* 4.5 usec */
        else
                val |= 3000 / 250; /* 3.0 usec */
        vlv_bunit_write(dev_priv, BUNIT_REG_BISOC, val);


Is this snippet applicable to BSW?

-- 
You are receiving this mail because:
You are the assignee for the bug.
You are the QA Contact for the bug.
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20161014/109741c4/attachment.html>