[PATCH 4/4] drm/i915: Detect USB-C specific dongles before reducing M and N
Daniel Vetter
daniel at ffwll.ch
Thu May 18 06:09:06 UTC 2017
On Wed, May 17, 2017 at 05:25:16PM +0300, Jani Nikula wrote:
> The Analogix 7737 DP to HDMI converter requires reduced M and N values
> when to operate correctly at HBR2. Detect this IC by its OUI value of
> 0x0022B9 via the DPCD quirk list.
Commit message is a bit confusing since this sounds like you're fixing
things for the offending analogix bridge, but what this does is fix things
for other broken chips. That part is only clear when looking at the Fixes:
commit and bug reports.
With the commit message fixed up to make this clear:
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Also patches 1&3 look good now, also Reviewed-by: Daniel Vetter
<daniel.vetter at ffwll.ch> for those.
Cheers, Daniel
>
> v2 by Jani: Rebased on the DP quirk database
>
> v3 by Jani: Rebased on the reworked DP quirk database
>
> 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 at intel.com>
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 3 ++-
> drivers/gpu/drm/i915/intel_display.c | 22 ++++++++++++++--------
> drivers/gpu/drm/i915/intel_dp.c | 8 ++++++--
> drivers/gpu/drm/i915/intel_dp_mst.c | 5 ++++-
> 4 files changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index a6f20471b4cd..699e07362044 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -563,7 +563,8 @@ struct intel_link_m_n {
>
> void intel_link_compute_m_n(int bpp, 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);
>
> /* Interface history:
> *
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 8217ed0e7132..ea4f116bd410 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6116,7 +6116,7 @@ static int ironlake_fdi_compute_config(struct intel_crtc *intel_crtc,
> 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) {
> @@ -6292,7 +6292,8 @@ 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
> @@ -6300,9 +6301,11 @@ 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);
> @@ -6313,16 +6316,19 @@ 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)
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 2a5f385e8f44..1ae9de5cf39c 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1627,6 +1627,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> int link_avail, link_clock;
> int common_len;
> uint8_t link_bw, rate_select;
> + bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
> + DP_DPCD_QUIRK_LIMITED_M_N);
>
> common_len = intel_dp_common_len_rate_limit(intel_dp,
> intel_dp->max_link_rate);
> @@ -1759,7 +1761,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> intel_link_compute_m_n(bpp, lane_count,
> adjusted_mode->crtc_clock,
> pipe_config->port_clock,
> - &pipe_config->dp_m_n);
> + &pipe_config->dp_m_n,
> + reduce_m_n);
>
> if (intel_connector->panel.downclock_mode != NULL &&
> dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) {
> @@ -1767,7 +1770,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> intel_link_compute_m_n(bpp, lane_count,
> intel_connector->panel.downclock_mode->clock,
> pipe_config->port_clock,
> - &pipe_config->dp_m2_n2);
> + &pipe_config->dp_m2_n2,
> + reduce_m_n);
> }
>
> /*
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index 68c788eb0b95..125917cebc60 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -44,6 +44,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> int lane_count, slots;
> const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> int mst_pbn;
> + bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
> + DP_DPCD_QUIRK_LIMITED_M_N);
>
> pipe_config->has_pch_encoder = false;
> bpp = 24;
> @@ -79,7 +81,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> intel_link_compute_m_n(bpp, lane_count,
> adjusted_mode->crtc_clock,
> pipe_config->port_clock,
> - &pipe_config->dp_m_n);
> + &pipe_config->dp_m_n,
> + reduce_m_n);
>
> pipe_config->dp_m_n.tu = slots;
>
> --
> 2.11.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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