| Message ID | 20211130212912.212044-1-lyude@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] drm/i915/dp: Perform 30ms delay after source OUI write | expand |
On Tue, 30 Nov 2021, Lyude Paul <lyude@redhat.com> wrote: > While working on supporting the Intel HDR backlight interface, I noticed > that there's a couple of laptops that will very rarely manage to boot up > without detecting Intel HDR backlight support - even though it's supported > on the system. One example of such a laptop is the Lenovo P17 1st > generation. > > Following some investigation Ville Syrjälä did through the docs they have > available to them, they discovered that there's actually supposed to be a > 30ms wait after writing the source OUI before we begin setting up the rest > of the backlight interface. > > This seems to be correct, as adding this 30ms delay seems to have > completely fixed the probing issues I was previously seeing. So - let's > start performing a 30ms wait after writing the OUI, which we do in a manner > similar to how we keep track of PPS delays (e.g. record the timestamp of > the OUI write, and then wait for however many ms are left since that > timestamp right before we interact with the backlight) in order to avoid > waiting any longer then we need to. As well, this also avoids us performing > this delay on systems where we don't end up using the HDR backlight > interface. > > V3: > * Move last_oui_write into intel_dp > V2: > * Move panel delays into intel_pps > > Signed-off-by: Lyude Paul <lyude@redhat.com> > Reviewed-by: Jani Nikula <jani.nikula@intel.com> > Fixes: 4a8d79901d5b ("drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)") > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> > Cc: <stable@vger.kernel.org> # v5.12+ Thanks, pushed to drm-intel-next. BR, Jani. > --- > drivers/gpu/drm/i915/display/intel_display_types.h | 3 +++ > drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++++ > drivers/gpu/drm/i915/display/intel_dp.h | 2 ++ > drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 5 +++++ > 4 files changed, 21 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h > index ea1e8a6e10b0..b9c967837872 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_types.h > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h > @@ -1653,6 +1653,9 @@ struct intel_dp { > struct intel_dp_pcon_frl frl; > > struct intel_psr psr; > + > + /* When we last wrote the OUI for eDP */ > + unsigned long last_oui_write; > }; > > enum lspcon_vendor { > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 0a424bf69396..5a8206298691 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -29,6 +29,7 @@ > #include <linux/i2c.h> > #include <linux/notifier.h> > #include <linux/slab.h> > +#include <linux/timekeeping.h> > #include <linux/types.h> > > #include <asm/byteorder.h> > @@ -2010,6 +2011,16 @@ intel_edp_init_source_oui(struct intel_dp *intel_dp, bool careful) > > if (drm_dp_dpcd_write(&intel_dp->aux, DP_SOURCE_OUI, oui, sizeof(oui)) < 0) > drm_err(&i915->drm, "Failed to write source OUI\n"); > + > + intel_dp->last_oui_write = jiffies; > +} > + > +void intel_dp_wait_source_oui(struct intel_dp *intel_dp) > +{ > + struct drm_i915_private *i915 = dp_to_i915(intel_dp); > + > + drm_dbg_kms(&i915->drm, "Performing OUI wait\n"); > + wait_remaining_ms_from_jiffies(intel_dp->last_oui_write, 30); > } > > /* If the device supports it, try to set the power state appropriately */ > diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h > index ce229026dc91..b64145a3869a 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.h > +++ b/drivers/gpu/drm/i915/display/intel_dp.h > @@ -119,4 +119,6 @@ void intel_dp_pcon_dsc_configure(struct intel_dp *intel_dp, > const struct intel_crtc_state *crtc_state); > void intel_dp_phy_test(struct intel_encoder *encoder); > > +void intel_dp_wait_source_oui(struct intel_dp *intel_dp); > + > #endif /* __INTEL_DP_H__ */ > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > index 8b9c925c4c16..62c112daacf2 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > @@ -36,6 +36,7 @@ > > #include "intel_backlight.h" > #include "intel_display_types.h" > +#include "intel_dp.h" > #include "intel_dp_aux_backlight.h" > > /* TODO: > @@ -106,6 +107,8 @@ intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector) > int ret; > u8 tcon_cap[4]; > > + intel_dp_wait_source_oui(intel_dp); > + > ret = drm_dp_dpcd_read(aux, INTEL_EDP_HDR_TCON_CAP0, tcon_cap, sizeof(tcon_cap)); > if (ret != sizeof(tcon_cap)) > return false; > @@ -204,6 +207,8 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state, > int ret; > u8 old_ctrl, ctrl; > > + intel_dp_wait_source_oui(intel_dp); > + > ret = drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &old_ctrl); > if (ret != 1) { > drm_err(&i915->drm, "Failed to read current backlight control mode: %d\n", ret);
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h index ea1e8a6e10b0..b9c967837872 100644 --- a/drivers/gpu/drm/i915/display/intel_display_types.h +++ b/drivers/gpu/drm/i915/display/intel_display_types.h @@ -1653,6 +1653,9 @@ struct intel_dp { struct intel_dp_pcon_frl frl; struct intel_psr psr; + + /* When we last wrote the OUI for eDP */ + unsigned long last_oui_write; }; enum lspcon_vendor { diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 0a424bf69396..5a8206298691 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -29,6 +29,7 @@ #include <linux/i2c.h> #include <linux/notifier.h> #include <linux/slab.h> +#include <linux/timekeeping.h> #include <linux/types.h> #include <asm/byteorder.h> @@ -2010,6 +2011,16 @@ intel_edp_init_source_oui(struct intel_dp *intel_dp, bool careful) if (drm_dp_dpcd_write(&intel_dp->aux, DP_SOURCE_OUI, oui, sizeof(oui)) < 0) drm_err(&i915->drm, "Failed to write source OUI\n"); + + intel_dp->last_oui_write = jiffies; +} + +void intel_dp_wait_source_oui(struct intel_dp *intel_dp) +{ + struct drm_i915_private *i915 = dp_to_i915(intel_dp); + + drm_dbg_kms(&i915->drm, "Performing OUI wait\n"); + wait_remaining_ms_from_jiffies(intel_dp->last_oui_write, 30); } /* If the device supports it, try to set the power state appropriately */ diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h index ce229026dc91..b64145a3869a 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.h +++ b/drivers/gpu/drm/i915/display/intel_dp.h @@ -119,4 +119,6 @@ void intel_dp_pcon_dsc_configure(struct intel_dp *intel_dp, const struct intel_crtc_state *crtc_state); void intel_dp_phy_test(struct intel_encoder *encoder); +void intel_dp_wait_source_oui(struct intel_dp *intel_dp); + #endif /* __INTEL_DP_H__ */ diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c index 8b9c925c4c16..62c112daacf2 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c @@ -36,6 +36,7 @@ #include "intel_backlight.h" #include "intel_display_types.h" +#include "intel_dp.h" #include "intel_dp_aux_backlight.h" /* TODO: @@ -106,6 +107,8 @@ intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector) int ret; u8 tcon_cap[4]; + intel_dp_wait_source_oui(intel_dp); + ret = drm_dp_dpcd_read(aux, INTEL_EDP_HDR_TCON_CAP0, tcon_cap, sizeof(tcon_cap)); if (ret != sizeof(tcon_cap)) return false; @@ -204,6 +207,8 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state, int ret; u8 old_ctrl, ctrl; + intel_dp_wait_source_oui(intel_dp); + ret = drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &old_ctrl); if (ret != 1) { drm_err(&i915->drm, "Failed to read current backlight control mode: %d\n", ret);