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| author | Jani Nikula <jani.nikula@intel.com> | 2017-05-18 14:10:25 +0300 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2017-05-29 13:43:47 +0300 |
| commit | b31e85eda38c58cae986162ae2c462b53b0a2065 (patch) | |
| tree | 5f7c60ad4e74c0d7c53d089b9f712ae6bd8d63f4 /drivers/gpu/drm/i915/intel_display.c | |
| parent | 76fa998acd86b6b40d0217e12af39c2406bdcd2b (diff) | |
| download | linux-b31e85eda38c58cae986162ae2c462b53b0a2065.tar.gz | |
drm/i915: Detect USB-C specific dongles before reducing M and N
The Analogix 7737 DP to HDMI converter requires reduced M and N values
when to operate correctly at HBR2. We tried to reduce the M/N values for
all devices in commit 9a86cda07af2 ("drm/i915/dp: reduce link M/N
parameters"), but that regressed some other sinks. Detect this IC by its
OUI value of 0x0022B9 via the DPCD quirk list, and only reduce the M/N
values for that.
v2 by Jani: Rebased on the DP quirk database
v3 by Jani: Rebased on the reworked DP quirk database
v4 by Jani: Improve commit message (Daniel)
Fixes: 9a86cda07af2 ("drm/i915/dp: reduce link M/N parameters")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93578
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100755
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/2d2e30f8f47d3f28c9b74ca2612336a54585c3ec.1495105635.git.jani.nikula@intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/intel_display.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 3617927af269..3cabe52a4e3b 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -6101,7 +6101,7 @@ retry: pipe_config->fdi_lanes = lane; intel_link_compute_m_n(pipe_config->pipe_bpp, lane, fdi_dotclock, - link_bw, &pipe_config->fdi_m_n); + link_bw, &pipe_config->fdi_m_n, false); ret = ironlake_check_fdi_lanes(dev, intel_crtc->pipe, pipe_config); if (ret == -EINVAL && pipe_config->pipe_bpp > 6*3) { @@ -6277,7 +6277,8 @@ intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den) } static void compute_m_n(unsigned int m, unsigned int n, - uint32_t *ret_m, uint32_t *ret_n) + uint32_t *ret_m, uint32_t *ret_n, + bool reduce_m_n) { /* * Reduce M/N as much as possible without loss in precision. Several DP @@ -6285,9 +6286,11 @@ static void compute_m_n(unsigned int m, unsigned int n, * values. The passed in values are more likely to have the least * significant bits zero than M after rounding below, so do this first. */ - while ((m & 1) == 0 && (n & 1) == 0) { - m >>= 1; - n >>= 1; + if (reduce_m_n) { + while ((m & 1) == 0 && (n & 1) == 0) { + m >>= 1; + n >>= 1; + } } *ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX); @@ -6298,16 +6301,19 @@ static void compute_m_n(unsigned int m, unsigned int 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) + struct intel_link_m_n *m_n, + bool reduce_m_n) { m_n->tu = 64; compute_m_n(bits_per_pixel * pixel_clock, link_clock * nlanes * 8, - &m_n->gmch_m, &m_n->gmch_n); + &m_n->gmch_m, &m_n->gmch_n, + reduce_m_n); compute_m_n(pixel_clock, link_clock, - &m_n->link_m, &m_n->link_n); + &m_n->link_m, &m_n->link_n, + reduce_m_n); } static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv) |