| Message ID | 20191218143416.v3.8.I251add713bc5c97225200894ab110ea9183434fd@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: ti-sn65dsi86: Improve support for AUO B116XAK01 + other DP | expand |
On Wed 18 Dec 14:35 PST 2019, Douglas Anderson wrote: > If we fail training at a lower DP link rate let's now keep trying > until we run out of rates to try. Basically the algorithm here is to > start at the link rate that is the theoretical minimum and then slowly > bump up until we run out of rates or hit the max rate of the sink. We > query the sink using a DPCD read. > > This is, in fact, important in practice. Specifically at least one > panel hooked up to the bridge (AUO B116XAK01) had a theoretical min > rate more than 1.62 GHz (if run at 24 bpp) and fails to train at the > next rate (2.16 GHz). It would train at 2.7 GHz, though. > > Signed-off-by: Douglas Anderson <dianders@chromium.org> > Tested-by: Rob Clark <robdclark@gmail.com> > Reviewed-by: Rob Clark <robdclark@gmail.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> > --- > > Changes in v3: None > Changes in v2: > - Squash in maybe-uninitialized fix from Rob Clark. > > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 71 ++++++++++++++++++++++----- > 1 file changed, 60 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > index 48fb4dc72e1c..e1b817ccd9c7 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > @@ -454,7 +454,7 @@ static const unsigned int ti_sn_bridge_dp_rate_lut[] = { > 0, 1620, 2160, 2430, 2700, 3240, 4320, 5400 > }; > > -static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) > +static int ti_sn_bridge_calc_min_dp_rate_idx(struct ti_sn_bridge *pdata) > { > unsigned int bit_rate_khz, dp_rate_mhz; > unsigned int i; > @@ -472,8 +472,42 @@ static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) > if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz) > break; > > - regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG, > - DP_DATARATE_MASK, DP_DATARATE(i)); > + return i; > +} > + > +static int ti_sn_bridge_get_max_dp_rate_idx(struct ti_sn_bridge *pdata) > +{ > + u8 data; > + int ret; > + > + ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &data); > + if (ret != 1) { > + DRM_DEV_ERROR(pdata->dev, > + "Can't read max rate (%d); assuming 5.4 GHz\n", > + ret); > + return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; > + } > + > + /* > + * Return an index into ti_sn_bridge_dp_rate_lut. Just hardcode > + * these indicies since it's not like the register spec is ever going > + * to change and a loop would just be more complicated. Apparently > + * the DP sink can only return these few rates as supported even > + * though the bridge allows some rates in between. > + */ > + switch (data) { > + case DP_LINK_BW_1_62: > + return 1; > + case DP_LINK_BW_2_7: > + return 4; > + case DP_LINK_BW_5_4: > + return 7; > + } > + > + DRM_DEV_ERROR(pdata->dev, > + "Unexpected max data rate (%#x); assuming 5.4 GHz\n", > + (int)data); > + return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; > } > > static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata) > @@ -530,13 +564,15 @@ static unsigned int ti_sn_get_max_lanes(struct ti_sn_bridge *pdata) > return data & DP_LANE_COUNT_MASK; > } > > -static int ti_sn_link_training(struct ti_sn_bridge *pdata) > +static int ti_sn_link_training(struct ti_sn_bridge *pdata, int dp_rate_idx, > + const char **last_err_str) > { > unsigned int val; > int ret; > > /* set dp clk frequency value */ > - ti_sn_bridge_set_dp_rate(pdata); > + regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG, > + DP_DATARATE_MASK, DP_DATARATE(dp_rate_idx)); > > /* enable DP PLL */ > regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1); > @@ -545,7 +581,7 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) > val & DPPLL_SRC_DP_PLL_LOCK, 1000, > 50 * 1000); > if (ret) { > - DRM_ERROR("DP_PLL_LOCK polling failed (%d)\n", ret); > + *last_err_str = "DP_PLL_LOCK polling failed"; > goto exit; > } > > @@ -556,9 +592,9 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) > val == ML_TX_NORMAL_MODE, 1000, > 500 * 1000); > if (ret) { > - DRM_ERROR("Training complete polling failed (%d)\n", ret); > + *last_err_str = "Training complete polling failed"; > } else if (val == ML_TX_MAIN_LINK_OFF) { > - DRM_ERROR("Link training failed, link is off\n"); > + *last_err_str = "Link training failed, link is off"; > ret = -EIO; > } > > @@ -573,8 +609,11 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) > static void ti_sn_bridge_enable(struct drm_bridge *bridge) > { > struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge); > + const char *last_err_str = "No supported DP rate"; > + int dp_rate_idx; > + int max_dp_rate_idx; > unsigned int val; > - int ret; > + int ret = -EINVAL; > > /* > * Run with the maximum number of lanes that the DP sink supports. > @@ -616,9 +655,19 @@ static void ti_sn_bridge_enable(struct drm_bridge *bridge) > regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK, > val); > > - ret = ti_sn_link_training(pdata); > - if (ret) > + /* Train until we run out of rates */ > + max_dp_rate_idx = ti_sn_bridge_get_max_dp_rate_idx(pdata); > + for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata); > + dp_rate_idx <= max_dp_rate_idx; > + dp_rate_idx++) { > + ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str); > + if (!ret) > + break; > + } > + if (ret) { > + DRM_DEV_ERROR(pdata->dev, "%s (%d)\n", last_err_str, ret); > return; > + } > > /* config video parameters */ > ti_sn_bridge_set_video_timings(pdata); > -- > 2.24.1.735.g03f4e72817-goog >
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 48fb4dc72e1c..e1b817ccd9c7 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -454,7 +454,7 @@ static const unsigned int ti_sn_bridge_dp_rate_lut[] = { 0, 1620, 2160, 2430, 2700, 3240, 4320, 5400 }; -static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) +static int ti_sn_bridge_calc_min_dp_rate_idx(struct ti_sn_bridge *pdata) { unsigned int bit_rate_khz, dp_rate_mhz; unsigned int i; @@ -472,8 +472,42 @@ static void ti_sn_bridge_set_dp_rate(struct ti_sn_bridge *pdata) if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz) break; - regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG, - DP_DATARATE_MASK, DP_DATARATE(i)); + return i; +} + +static int ti_sn_bridge_get_max_dp_rate_idx(struct ti_sn_bridge *pdata) +{ + u8 data; + int ret; + + ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &data); + if (ret != 1) { + DRM_DEV_ERROR(pdata->dev, + "Can't read max rate (%d); assuming 5.4 GHz\n", + ret); + return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; + } + + /* + * Return an index into ti_sn_bridge_dp_rate_lut. Just hardcode + * these indicies since it's not like the register spec is ever going + * to change and a loop would just be more complicated. Apparently + * the DP sink can only return these few rates as supported even + * though the bridge allows some rates in between. + */ + switch (data) { + case DP_LINK_BW_1_62: + return 1; + case DP_LINK_BW_2_7: + return 4; + case DP_LINK_BW_5_4: + return 7; + } + + DRM_DEV_ERROR(pdata->dev, + "Unexpected max data rate (%#x); assuming 5.4 GHz\n", + (int)data); + return ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; } static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata) @@ -530,13 +564,15 @@ static unsigned int ti_sn_get_max_lanes(struct ti_sn_bridge *pdata) return data & DP_LANE_COUNT_MASK; } -static int ti_sn_link_training(struct ti_sn_bridge *pdata) +static int ti_sn_link_training(struct ti_sn_bridge *pdata, int dp_rate_idx, + const char **last_err_str) { unsigned int val; int ret; /* set dp clk frequency value */ - ti_sn_bridge_set_dp_rate(pdata); + regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG, + DP_DATARATE_MASK, DP_DATARATE(dp_rate_idx)); /* enable DP PLL */ regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1); @@ -545,7 +581,7 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) val & DPPLL_SRC_DP_PLL_LOCK, 1000, 50 * 1000); if (ret) { - DRM_ERROR("DP_PLL_LOCK polling failed (%d)\n", ret); + *last_err_str = "DP_PLL_LOCK polling failed"; goto exit; } @@ -556,9 +592,9 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) val == ML_TX_NORMAL_MODE, 1000, 500 * 1000); if (ret) { - DRM_ERROR("Training complete polling failed (%d)\n", ret); + *last_err_str = "Training complete polling failed"; } else if (val == ML_TX_MAIN_LINK_OFF) { - DRM_ERROR("Link training failed, link is off\n"); + *last_err_str = "Link training failed, link is off"; ret = -EIO; } @@ -573,8 +609,11 @@ static int ti_sn_link_training(struct ti_sn_bridge *pdata) static void ti_sn_bridge_enable(struct drm_bridge *bridge) { struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge); + const char *last_err_str = "No supported DP rate"; + int dp_rate_idx; + int max_dp_rate_idx; unsigned int val; - int ret; + int ret = -EINVAL; /* * Run with the maximum number of lanes that the DP sink supports. @@ -616,9 +655,19 @@ static void ti_sn_bridge_enable(struct drm_bridge *bridge) regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK, val); - ret = ti_sn_link_training(pdata); - if (ret) + /* Train until we run out of rates */ + max_dp_rate_idx = ti_sn_bridge_get_max_dp_rate_idx(pdata); + for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata); + dp_rate_idx <= max_dp_rate_idx; + dp_rate_idx++) { + ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str); + if (!ret) + break; + } + if (ret) { + DRM_DEV_ERROR(pdata->dev, "%s (%d)\n", last_err_str, ret); return; + } /* config video parameters */ ti_sn_bridge_set_video_timings(pdata);