Re: [PATCH] drm/i915: cache the EDID for eDP panels

Jani Nikula
2012-06-15T07:31:59Z

On Thu, 14 Jun 2012, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> They aren't going anywhere, and probing on DDC can cause the panel to
> blank briefly, so read them up front and cache them for later queries.
>
> v2: fix potential NULL derefs in intel_dp_get_edid_modes and
> intel_dp_get_edid (Jani)
> copy full EDID length, including extension blocks (Takashi)
> free EDID on teardown (Takashi)
> v3: malloc a new EDID buffer that's big enough for the memcpy (Chris)
> v4: change handling of NULL EDIDs, just preserve the NULL behavior
> across detects and mode list fetches rather than trying to re-fetch
> the EDID (Chris)
> v5: be glad that Chris is around to remind me to hit C-x C-s before
> committing.
>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=46856
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 49 ++++++++++++++++++++++++++++++++++-----
> 1 file changed, 43 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 6538c46..69d2f0c 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -32,6 +32,7 @@
> #include "drm.h"
> #include "drm_crtc.h"
> #include "drm_crtc_helper.h"
> +#include "drm_edid.h"
> #include "intel_drv.h"
> #include "i915_drm.h"
> #include "i915_drv.h"
> @@ -67,6 +68,8 @@ struct intel_dp {
> struct drm_display_mode *panel_fixed_mode; /* for eDP */
> struct delayed_work panel_vdd_work;
> bool want_panel_vdd;
> + struct edid *edid; /* cached EDID for eDP */
> + int edid_mode_count;
> };
>
> /**
> @@ -2121,10 +2124,22 @@ intel_dp_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
> {
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct edid *edid;
> + int size;
> +
> + if (is_edp(intel_dp)) {
> + if (!intel_dp->edid)
> + return NULL;
> +
> + size = (intel_dp->edid->extensions + 1) * EDID_LENGTH;
> + edid = kmalloc(size, GFP_KERNEL);
> + if (!edid)
> + return NULL;
> +
> + memcpy(edid, intel_dp->edid, size);
> + return edid;
> + }
>
> - ironlake_edp_panel_vdd_on(intel_dp);
> edid = drm_get_edid(connector, adapter);
> - ironlake_edp_panel_vdd_off(intel_dp, false);
> return edid;
> }
>
> @@ -2134,9 +2149,17 @@ intel_dp_get_edid_modes(struct drm_connector *connector, struct i2c_adapter *ada
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> int ret;
>
> - ironlake_edp_panel_vdd_on(intel_dp);
> + if (is_edp(intel_dp)) {
> + drm_mode_connector_update_edid_property(connector,
> + intel_dp->edid);
> + ret = drm_add_edid_modes(connector, intel_dp->edid);

Hi Jesse, I'm sure you meant to do *something* with that return value. I
presume it should be equal to intel_dp->edid_mode_count, but is it
possible it's not? Is it better to return ret or
intel_dp->edid_mode_count from this function?

BR,
Jani.

> + drm_edid_to_eld(connector,
> + intel_dp->edid);
> + connector->display_info.raw_edid = NULL;
> + return intel_dp->edid_mode_count;
> + }
> +
> ret = intel_ddc_get_modes(connector, adapter);
> - ironlake_edp_panel_vdd_off(intel_dp, false);
> return ret;
> }
>
> @@ -2326,6 +2349,7 @@ static void intel_dp_encoder_destroy(struct drm_encoder *encoder)
> i2c_del_adapter(&intel_dp->adapter);
> drm_encoder_cleanup(encoder);
> if (is_edp(intel_dp)) {
> + kfree(intel_dp->edid);
> cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
> ironlake_panel_vdd_off_sync(intel_dp);
> }
> @@ -2509,11 +2533,14 @@ intel_dp_init(struct drm_device *dev, int output_reg)
> break;
> }
>
> + intel_dp_i2c_init(intel_dp, intel_connector, name);
> +
> /* Cache some DPCD data in the eDP case */
> if (is_edp(intel_dp)) {
> bool ret;
> struct edp_power_seq cur, vbt;
> u32 pp_on, pp_off, pp_div;
> + struct edid *edid;
>
> pp_on = I915_READ(PCH_PP_ON_DELAYS);
> pp_off = I915_READ(PCH_PP_OFF_DELAYS);
> @@ -2581,9 +2608,19 @@ intel_dp_init(struct drm_device *dev, int output_reg)
> intel_dp_destroy(&intel_connector->base);
> return;
> }
> - }
>
> - intel_dp_i2c_init(intel_dp, intel_connector, name);
> + ironlake_edp_panel_vdd_on(intel_dp);
> + edid = drm_get_edid(connector, &intel_dp->adapter);
> + if (edid) {
> + drm_mode_connector_update_edid_property(connector,
> + edid);
> + intel_dp->edid_mode_count =
> + drm_add_edid_modes(connector, edid);
> + drm_edid_to_eld(connector, edid);
> + intel_dp->edid = edid;
> + }
> + ironlake_edp_panel_vdd_off(intel_dp, false);
> + }
>
> intel_encoder->hot_plug = intel_dp_hot_plug;
>
> --
> 1.7.9.5
>
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