From: Jani Nikula <jani.nikula@linux.intel.com>
To: Lyude Paul <lyude@redhat.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Dave Airlie <airlied@gmail.com>,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Cc: thaytan@noraisin.net, "Vasily Khoruzhick" <anarsoul@gmail.com>,
"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
"David Airlie" <airlied@linux.ie>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Juha-Pekka Heikkila" <juhapekka.heikkila@gmail.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Sean Paul" <seanpaul@chromium.org>,
"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 8/9] drm/i915/dp: Allow forcing specific interfaces through enable_dpcd_backlight
Date: Wed, 23 Dec 2020 19:12:53 +0200 [thread overview]
Message-ID: <87tuscmooa.fsf@intel.com> (raw)
In-Reply-To: <20201204223603.249878-9-lyude@redhat.com>
On Fri, 04 Dec 2020, Lyude Paul <lyude@redhat.com> wrote:
> Since we now support controlling panel backlights through DPCD using
> both the standard VESA interface, and Intel's proprietary HDR backlight
> interface, we should allow the user to be able to explicitly choose
> between one or the other in the event that we're wrong about panels
> reliably reporting support for the Intel HDR interface.
>
> So, this commit adds support for this by introducing two new
> enable_dpcd_backlight options: 2 which forces i915 to only probe for the
> VESA interface, and 3 which forces i915 to only probe for the Intel
> backlight interface (might be useful if we find panels in the wild that
> report the VESA interface in their VBT, but actually only support the
> Intel backlight interface).
>
> v3:
> * Rebase
>
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Cc: thaytan@noraisin.net
> Cc: Vasily Khoruzhick <anarsoul@gmail.com>
> ---
> .../drm/i915/display/intel_dp_aux_backlight.c | 45 +++++++++++++++++--
> drivers/gpu/drm/i915/i915_params.c | 2 +-
> 2 files changed, 43 insertions(+), 4 deletions(-)
>
> 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 9a3ff3ffc158..eef14ab6bddc 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -609,15 +609,54 @@ static const struct intel_panel_bl_funcs intel_dp_vesa_bl_funcs = {
> .get = intel_dp_aux_vesa_get_backlight,
> };
>
> +enum intel_dp_aux_backlight_modparam {
> + INTEL_DP_AUX_BACKLIGHT_AUTO = -1,
> + INTEL_DP_AUX_BACKLIGHT_OFF = 0,
> + INTEL_DP_AUX_BACKLIGHT_ON = 1,
> + INTEL_DP_AUX_BACKLIGHT_FORCE_VESA = 2,
> + INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL = 3,
> +};
> +
> int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
> {
> struct drm_device *dev = connector->base.dev;
> struct intel_panel *panel = &connector->panel;
> struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + bool try_intel_interface = false, try_vesa_interface = false;
>
> - if (i915->params.enable_dpcd_backlight == 0)
> + /* Check the VBT and user's module parameters to figure out which
> + * interfaces to probe
> + */
> + switch (i915->params.enable_dpcd_backlight) {
> + case INTEL_DP_AUX_BACKLIGHT_OFF:
> return -ENODEV;
> + case INTEL_DP_AUX_BACKLIGHT_AUTO:
> + switch (i915->vbt.backlight.type) {
> + case INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE:
> + try_vesa_interface = true;
> + break;
> + case INTEL_BACKLIGHT_DISPLAY_DDI:
> + try_intel_interface = true;
I take it this is what the machines report? *rolls eyes*.
> + try_vesa_interface = true;
> + break;
> + default:
> + return -ENODEV;
> + }
> + break;
> + case INTEL_DP_AUX_BACKLIGHT_ON:
> + if (i915->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE)
> + try_intel_interface = true;
This could use an explanation - why not try the intel interface in this
case?
Anyway, good enough,
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
> +
> + try_vesa_interface = true;
> + break;
> + case INTEL_DP_AUX_BACKLIGHT_FORCE_VESA:
> + try_vesa_interface = true;
> + break;
> + case INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL:
> + try_intel_interface = true;
> + break;
> + }
>
> /*
> * A lot of eDP panels in the wild will report supporting both the
> @@ -626,13 +665,13 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
> * and will only work with the Intel interface. So, always probe for
> * that first.
> */
> - if (intel_dp_aux_supports_hdr_backlight(connector)) {
> + if (try_intel_interface && intel_dp_aux_supports_hdr_backlight(connector)) {
> drm_dbg(dev, "Using Intel proprietary eDP backlight controls\n");
> panel->backlight.funcs = &intel_dp_hdr_bl_funcs;
> return 0;
> }
>
> - if (intel_dp_aux_supports_vesa_backlight(connector)) {
> + if (try_vesa_interface && intel_dp_aux_supports_vesa_backlight(connector)) {
> drm_dbg(dev, "Using VESA eDP backlight controls\n");
> panel->backlight.funcs = &intel_dp_vesa_bl_funcs;
> return 0;
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index 7f139ea4a90b..6939634e56ed 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -185,7 +185,7 @@ i915_param_named_unsafe(inject_probe_failure, uint, 0400,
>
> i915_param_named(enable_dpcd_backlight, int, 0400,
> "Enable support for DPCD backlight control"
> - "(-1=use per-VBT LFP backlight type setting [default], 0=disabled, 1=enabled)");
> + "(-1=use per-VBT LFP backlight type setting [default], 0=disabled, 1=enable, 2=force VESA interface, 3=force Intel interface)");
>
> #if IS_ENABLED(CONFIG_DRM_I915_GVT)
> i915_param_named(enable_gvt, bool, 0400,
--
Jani Nikula, Intel Open Source Graphics Center
next prev parent reply other threads:[~2020-12-23 17:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20201204223603.249878-1-lyude@redhat.com>
2020-12-04 22:35 ` [PATCH v3 1/9] drm/i915/dp: Program source OUI on eDP panels Lyude Paul
2020-12-04 22:35 ` [PATCH v3 2/9] drm/i915: Rename pwm_* backlight callbacks to ext_pwm_* Lyude Paul
2020-12-04 22:35 ` [PATCH v3 3/9] drm/i915: Pass down brightness values to enable/disable backlight callbacks Lyude Paul
2020-12-04 22:35 ` [PATCH v3 4/9] drm/i915: Keep track of pwm-related backlight hooks separately Lyude Paul
2020-12-23 16:37 ` Jani Nikula
2021-01-05 21:21 ` Lyude Paul
2020-12-04 22:35 ` [PATCH v3 5/9] drm/i915/dp: Rename eDP VESA backlight interface functions Lyude Paul
2020-12-04 22:36 ` [PATCH v3 6/9] drm/i915/dp: Add register definitions for Intel HDR backlight interface Lyude Paul
2020-12-04 22:36 ` [PATCH v3 7/9] drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now) Lyude Paul
2020-12-23 17:05 ` Jani Nikula
2020-12-04 22:36 ` [PATCH v3 8/9] drm/i915/dp: Allow forcing specific interfaces through enable_dpcd_backlight Lyude Paul
2020-12-23 17:12 ` Jani Nikula [this message]
2020-12-04 22:36 ` [PATCH v3 9/9] drm/dp: Revert "drm/dp: Introduce EDID-based quirks" Lyude Paul
2020-12-05 8:12 ` kernel test robot
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