On Mon, Apr 22, 2013 at 05:23:50PM +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> Since it took me a while to fire up my brain and understand the magic values ... can we please have some #defines for the magic 23 = 24 -1 and the magic 0xffffff = 1 << (24) - 1 ? Also maybe call intel_reduce_ratio intel_reduce_m_n_ratio or so while at it. > --- > 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. It's pretty early for 3.10, so I think we can just stick this into -fixes and see what happens. -Daniel > > 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) > -- > 1.8.1.5 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
