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Message-ID: <87v9p1gk4z.fsf@intel.com>
Date: Fri, 24 Jan 2020 13:37:48 +0200
From: Jani Nikula <jani.nikula@...ux.intel.com>
To: Rajat Jain <rajatja@...gle.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
Ville Syrjälä <ville.syrjala@...ux.intel.com>,
Chris Wilson <chris@...is-wilson.co.uk>,
Imre Deak <imre.deak@...el.com>,
José Roberto de Souza <jose.souza@...el.com>,
linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
intel-gfx@...ts.freedesktop.org, gregkh@...uxfoundation.org,
mathewk@...gle.com, Daniel Thompson <daniel.thompson@...aro.org>,
Jonathan Corbet <corbet@....net>, Pavel Machek <pavel@...x.de>,
seanpaul@...gle.com, Duncan Laurie <dlaurie@...gle.com>,
jsbarnes@...gle.com, Thierry Reding <thierry.reding@...il.com>
Cc: Rajat Jain <rajatja@...gle.com>, rajatxjain@...il.com
Subject: Re: [PATCH v5 2/3] drm/i915: Lookup and attach ACPI device node for connectors
On Fri, 20 Dec 2019, Rajat Jain <rajatja@...gle.com> wrote:
> Lookup and attach ACPI nodes for intel connectors. The lookup is done
> in compliance with ACPI Spec 6.3
> https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> (Ref: Pages 1119 - 1123).
>
> This can be useful for any connector specific platform properties. (This
> will be used for privacy screen in next patch).
>
> Signed-off-by: Rajat Jain <rajatja@...gle.com>
> ---
> v5: same as v4
> v4: Same as v3
> v3: fold the code into existing acpi_device_id_update() function
> v2: formed by splitting the original patch into ACPI lookup, and privacy
> screen property. Also move it into i915 now that I found existing code
> in i915 that can be re-used.
>
> drivers/gpu/drm/i915/display/intel_acpi.c | 24 +++++++++++++++++++
> .../drm/i915/display/intel_display_types.h | 3 +++
> drivers/gpu/drm/i915/display/intel_dp.c | 3 +++
> 3 files changed, 30 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
> index e21fb14d5e07..101a56c08996 100644
> --- a/drivers/gpu/drm/i915/display/intel_acpi.c
> +++ b/drivers/gpu/drm/i915/display/intel_acpi.c
> @@ -222,11 +222,23 @@ static u32 acpi_display_type(struct intel_connector *connector)
> return display_type;
> }
>
> +/*
> + * Ref: ACPI Spec 6.3
> + * https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> + * Pages 1119 - 1123 describe, what I believe, a standard way of
> + * identifying / addressing "display panels" in the ACPI. It provides
> + * a way for the ACPI to define devices for the display panels attached
> + * to the system. It thus provides a way for the BIOS to export any panel
> + * specific properties to the system via ACPI (like device trees).
> + */
> void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
> {
> struct drm_device *drm_dev = &dev_priv->drm;
> struct intel_connector *connector;
> struct drm_connector_list_iter conn_iter;
> + struct device *dev = &drm_dev->pdev->dev;
Hmm, already pushed patch 1 with the unfortunate "drm_dev" local. We use
"dev" for struct drm_device * and almost never use struct device.
> + struct acpi_device *conn_dev;
> + u64 conn_addr;
> u8 display_index[16] = {};
>
> /* Populate the ACPI IDs for all connectors for a given drm_device */
> @@ -242,6 +254,18 @@ void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
> device_id |= display_index[type]++ << ACPI_DISPLAY_INDEX_SHIFT;
>
> connector->acpi_device_id = device_id;
> +
> + /* Build the _ADR to look for */
> + conn_addr = device_id | ACPI_DEVICE_ID_SCHEME |
> + ACPI_BIOS_CAN_DETECT;
> +
> + DRM_DEV_INFO(dev, "Checking connector ACPI node at _ADR=%llX\n",
> + conn_addr);
This is more than a little verbose. One line of INFO level dmesg for
every connector at boot and at resume.
Please use the new drm_dbg_kms() macro for this.
> +
> + /* Look up the connector device, under the PCI device */
> + conn_dev = acpi_find_child_device(ACPI_COMPANION(dev),
> + conn_addr, false);
> + connector->acpi_handle = conn_dev ? conn_dev->handle : NULL;
acpi_device_handle(conn_dev)
> }
> drm_connector_list_iter_end(&conn_iter);
> }
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 1a7334dbe802..0a4a04116091 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -407,6 +407,9 @@ struct intel_connector {
> /* ACPI device id for ACPI and driver cooperation */
> u32 acpi_device_id;
>
> + /* ACPI handle corresponding to this connector display, if found */
> + void *acpi_handle;
> +
The type is acpi_handle. It's none of our business to know what the
underlying type is.
> /* Reads out the current hw, returning true if the connector is enabled
> * and active (i.e. dpms ON state). */
> bool (*get_hw_state)(struct intel_connector *);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index b05b2191b919..93cece8e2516 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -45,6 +45,7 @@
> #include "i915_debugfs.h"
> #include "i915_drv.h"
> #include "i915_trace.h"
> +#include "intel_acpi.h"
> #include "intel_atomic.h"
> #include "intel_audio.h"
> #include "intel_connector.h"
> @@ -6623,6 +6624,8 @@ intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connect
>
> connector->state->scaling_mode = DRM_MODE_SCALE_ASPECT;
>
> + /* Lookup the ACPI node corresponding to the connector */
> + intel_acpi_device_id_update(dev_priv);
Auch, this is problematic. It iterates all connectors, for every DP
connector being added. In the middle of registering all connectors.
>From the POV of this patch alone, this is also unnecessary. This gets
called via intel_opregion_register() after all connectors have been
registered.
I am aware it's not enough for your next patch, because it will need the
acpi handle right here.
I'm wondering if we need to maintain display_index[] in struct
drm_i915_private, and update that as connectors get added instead of all
at once in the end. connector->acpi_device_id never changes, does it,
even though we keep updating it?
BR,
Jani.
> }
> }
--
Jani Nikula, Intel Open Source Graphics Center
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