On Mon, 22 Apr 2013 17:23:50 +0300 ville.syrjala at linux.intel.com wrote: > From: Ville Syrj?l? <ville.syrjala at linux.intel.com> > > The BIOS uses power of two values for the data/link N value. > > Follow suit to make the Zotac DP to dual-HDMI dongle work. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402 > Signed-off-by: Ville Syrj?l? <ville.syrjala at linux.intel.com> > --- > Warning: I've only tested this with the Zotac dongle hooked to my 1080p > Samsumg telly. Whether or not it works with other displays is an open > question. > > drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > index 74156e2..fea9c99 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -4151,18 +4151,29 @@ intel_reduce_ratio(uint32_t *num, uint32_t *den) > } > } > > +static void compute_m_n(int m, int n, uint32_t *ret_m, uint32_t *ret_n) > +{ > + if (n >= 1 << 23) > + *ret_n = 1 << 23; > + else > + *ret_n = roundup_pow_of_two(n); > + *ret_m = div_u64((uint64_t) m * *ret_n, n); > + intel_reduce_ratio(ret_m, ret_n); > +} > + > void > intel_link_compute_m_n(int bits_per_pixel, int nlanes, > int pixel_clock, int link_clock, > struct intel_link_m_n *m_n) > { > m_n->tu = 64; > - m_n->gmch_m = bits_per_pixel * pixel_clock; > - m_n->gmch_n = link_clock * nlanes * 8; > - intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n); > - m_n->link_m = pixel_clock; > - m_n->link_n = link_clock; > - intel_reduce_ratio(&m_n->link_m, &m_n->link_n); > + > + compute_m_n(bits_per_pixel * pixel_clock, > + link_clock * nlanes * 8, > + &m_n->gmch_m, &m_n->gmch_n); > + > + compute_m_n(pixel_clock, link_clock, > + &m_n->link_m, &m_n->link_n); > } > > static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv) You can add my Tested-by: to this one, it seems to fix https://bugs.freedesktop.org/show_bug.cgi?id=59810 as well. Art, is this something we've just missed and should have been doing all along? Thanks, -- Jesse Barnes, Intel Open Source Technology Center
