Re: [PATCH v5] drm/i915/edp: Allow alternate fixed mode for eDP if available.

David Weinehall
2017-08-03T07:30:54Z

On Fri, Jul 28, 2017 at 12:22:29PM -0700, Jim Bride wrote:
> Some fixed resolution panels actually support more than one mode,
> with the only thing different being the refresh rate. Having this
> alternate mode available to us is desirable, because it allows us to
> test PSR on panels whose setup time at the preferred mode is too long.
> With this patch we allow the use of the alternate mode if it's
> available and it was specifically requested.
>
> v2 and v3: Rebase
> v4: * Fix up some leaky mode stuff (Chris)
> * Rebase
> v5: * Fix a NULL pointer derefreence (David Weinehall)

dereference

I've tested your patch series, and with the v5 version of this patch
plus the v4 versions of the other patches my Skylake laptop no longer
oopses on boot. I've also tested this on a Haswell laptop that had
working PSR even without this patch, to make sure that this doesn't
introduce any regressions.

Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>

with minor nitpicks.

>
> Cc: David Weinehall <david.weinehall@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Jim Bride <jim.bride@linux.intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 38 +++++++++++++++++++++++++++++++++-----
> drivers/gpu/drm/i915/intel_drv.h | 2 ++
> drivers/gpu/drm/i915/intel_dsi.c | 2 +-
> drivers/gpu/drm/i915/intel_dvo.c | 2 +-
> drivers/gpu/drm/i915/intel_lvds.c | 3 ++-
> drivers/gpu/drm/i915/intel_panel.c | 6 ++++++
> 6 files changed, 45 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 7c0e530..60c4642 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1606,6 +1606,23 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
> return bpp;
> }
>
> +static bool intel_edp_compare_alt_mode(struct drm_display_mode *m1,
> + struct drm_display_mode *m2)
> +{
> + bool bres = false;
> +

Whitespace error (git apply warns)

> + if (m1 && m2)
> + bres = (m1->hdisplay == m2->hdisplay &&

Dunno if it warns about this too, but methinks that double space is
erroneous.

> + m1->hsync_start == m2->hsync_start &&
> + m1->hsync_end == m2->hsync_end &&
> + m1->htotal == m2->htotal &&
> + m1->vdisplay == m2->vdisplay &&
> + m1->vsync_start == m2->vsync_start &&
> + m1->vsync_end == m2->vsync_end &&
> + m1->vtotal == m2->vtotal);
> + return bres;
> +}
> +
> bool
> intel_dp_compute_config(struct intel_encoder *encoder,
> struct intel_crtc_state *pipe_config,
> @@ -1652,8 +1669,16 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> pipe_config->has_audio = intel_conn_state->force_audio == HDMI_AUDIO_ON;
>
> if (is_edp(intel_dp) && intel_connector->panel.fixed_mode) {
> - intel_fixed_panel_mode(intel_connector->panel.fixed_mode,
> - adjusted_mode);
> + struct drm_display_mode *panel_mode =
> + intel_connector->panel.alt_fixed_mode;
> + struct drm_display_mode *req_mode = &pipe_config->base.mode;
> +
> + if (!intel_edp_compare_alt_mode(req_mode, panel_mode))
> + panel_mode = intel_connector->panel.fixed_mode;
> +
> + drm_mode_debug_printmodeline(panel_mode);
> +
> + intel_fixed_panel_mode(panel_mode, adjusted_mode);
>
> if (INTEL_GEN(dev_priv) >= 9) {
> int ret;
> @@ -5810,6 +5835,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> struct drm_device *dev = intel_encoder->base.dev;
> struct drm_i915_private *dev_priv = to_i915(dev);
> struct drm_display_mode *fixed_mode = NULL;
> + struct drm_display_mode *alt_fixed_mode = NULL;
> struct drm_display_mode *downclock_mode = NULL;
> bool has_dpcd;
> struct drm_display_mode *scan;
> @@ -5865,13 +5891,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> }
> intel_connector->edid = edid;
>
> - /* prefer fixed mode from EDID if available */
> + /* prefer fixed mode from EDID if available, save an alt mode also */
> list_for_each_entry(scan, &connector->probed_modes, head) {
> if ((scan->type & DRM_MODE_TYPE_PREFERRED)) {
> fixed_mode = drm_mode_duplicate(dev, scan);
> downclock_mode = intel_dp_drrs_init(
> intel_connector, fixed_mode);
> - break;
> + } else if (!alt_fixed_mode) {
> + alt_fixed_mode = drm_mode_duplicate(dev, scan);
> }
> }
>
> @@ -5908,7 +5935,8 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> pipe_name(pipe));
> }
>
> - intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
> + intel_panel_init(&intel_connector->panel, fixed_mode, alt_fixed_mode,
> + downclock_mode);
> intel_connector->panel.backlight.power = intel_edp_backlight_power;
> intel_panel_setup_backlight(connector, pipe);
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 046d358..00bde65 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -265,6 +265,7 @@ struct intel_encoder {
>
> struct intel_panel {
> struct drm_display_mode *fixed_mode;
> + struct drm_display_mode *alt_fixed_mode;
> struct drm_display_mode *downclock_mode;
>
> /* backlight */
> @@ -1682,6 +1683,7 @@ void intel_overlay_reset(struct drm_i915_private *dev_priv);
> /* intel_panel.c */
> int intel_panel_init(struct intel_panel *panel,
> struct drm_display_mode *fixed_mode,
> + struct drm_display_mode *alt_fixed_mode,
> struct drm_display_mode *downclock_mode);
> void intel_panel_fini(struct intel_panel *panel);
> void intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 50ec836..d3a6608 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -1851,7 +1851,7 @@ void intel_dsi_init(struct drm_i915_private *dev_priv)
> connector->display_info.width_mm = fixed_mode->width_mm;
> connector->display_info.height_mm = fixed_mode->height_mm;
>
> - intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
> + intel_panel_init(&intel_connector->panel, fixed_mode, NULL, NULL);
> intel_panel_setup_backlight(connector, INVALID_PIPE);
>
> intel_dsi_add_properties(intel_connector);
> diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
> index c1544a5..39fd4f3 100644
> --- a/drivers/gpu/drm/i915/intel_dvo.c
> +++ b/drivers/gpu/drm/i915/intel_dvo.c
> @@ -554,7 +554,7 @@ void intel_dvo_init(struct drm_i915_private *dev_priv)
> */
> intel_panel_init(&intel_connector->panel,
> intel_dvo_get_current_mode(connector),
> - NULL);
> + NULL, NULL);
> intel_dvo->panel_wants_dither = true;
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> index 6fe5d7c..a995ccb 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -1140,7 +1140,8 @@ void intel_lvds_init(struct drm_i915_private *dev_priv)
> out:
> mutex_unlock(&dev->mode_config.mutex);
>
> - intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
> + intel_panel_init(&intel_connector->panel, fixed_mode, NULL,
> + downclock_mode);
> intel_panel_setup_backlight(connector, INVALID_PIPE);
>
> lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder);
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index fd2e081..e7df774 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -1920,11 +1920,13 @@ intel_panel_init_backlight_funcs(struct intel_panel *panel)
>
> int intel_panel_init(struct intel_panel *panel,
> struct drm_display_mode *fixed_mode,
> + struct drm_display_mode *alt_fixed_mode,
> struct drm_display_mode *downclock_mode)
> {
> intel_panel_init_backlight_funcs(panel);
>
> panel->fixed_mode = fixed_mode;
> + panel->alt_fixed_mode = alt_fixed_mode;
> panel->downclock_mode = downclock_mode;
>
> return 0;
> @@ -1938,6 +1940,10 @@ void intel_panel_fini(struct intel_panel *panel)
> if (panel->fixed_mode)
> drm_mode_destroy(intel_connector->base.dev, panel->fixed_mode);
>
> + if (panel->alt_fixed_mode)
> + drm_mode_destroy(intel_connector->base.dev,
> + panel->alt_fixed_mode);
> +
> if (panel->downclock_mode)
> drm_mode_destroy(intel_connector->base.dev,
> panel->downclock_mode);
> --
> 2.7.4
>