diff options
| author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2013-04-23 15:03:34 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2013-04-23 22:19:26 +0200 |
| commit | a65851af59387146a28a928c3e7bb17dabc5db72 (patch) | |
| tree | 7207836d2c2fdfbe933d790a6dc3186ebd681059 /drivers/gpu/drm/i915/intel_display.c | |
| parent | ae4edb8089df67d25fbd9386012a335a64aca287 (diff) | |
drm/i915: Make data/link N value power of two
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.
v2: Clean up the magic numbers and defines
Change the N clamping to be a bit easier on the eye
Rename intel_reduce_ratio to intel_reduce_m_n_ratio
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59810
Tested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_display.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 6e423e04c35..efe82991975 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4084,26 +4084,36 @@ static int i830_get_display_clock_speed(struct drm_device *dev) } static void -intel_reduce_ratio(uint32_t *num, uint32_t *den) +intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den) { - while (*num > 0xffffff || *den > 0xffffff) { + while (*num > DATA_LINK_M_N_MASK || + *den > DATA_LINK_M_N_MASK) { *num >>= 1; *den >>= 1; } } +static void compute_m_n(unsigned int m, unsigned int n, + uint32_t *ret_m, uint32_t *ret_n) +{ + *ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX); + *ret_m = div_u64((uint64_t) m * *ret_n, n); + intel_reduce_m_n_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) |