Re: [PATCH v5 2/7] drm/panel: simple: Add ability to override typical timing

Hi Dough.

On Mon, Jul 01, 2019 at 09:39:24AM -0700, Doug Anderson wrote:

Hi,

On Sun, Jun 30, 2019 at 1:22 PM Sam Ravnborg [off-list ref] wrote:

quoted

quoted

@@ -91,6 +92,8 @@ struct panel_simple {
      struct i2c_adapter *ddc;

      struct gpio_desc *enable_gpio;
+
+     struct drm_display_mode override_mode;

I fail to see where this poiter is assigned.

In panel_simple_parse_override_mode().  Specifically:

drm_display_mode_from_videomode(&vm, &panel->override_mode);

The above code-snippet is only called in the panel has specified display
timings using display_timings - it is not called when display_mode is
used.
So override_mode is only assigned in some cases and not all cases.
This needs to be fixed so we do not reference override_mode unless
it is set.

quoted

@@ -152,6 +162,44 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)

quoted

              num++;
      }

+     return num;
+}
+
+static int panel_simple_get_non_edid_modes(struct panel_simple *panel)
+{
+     struct drm_connector *connector = panel->base.connector;
+     struct drm_device *drm = panel->base.drm;
+     struct drm_display_mode *mode;
+     bool has_override = panel->override_mode.type;

This looks suspicious.
panel->override_mode.type is an unsigned int that may have a number of
bits set.
So the above code implicitly convert a .type != 0 to a true.
This can be expressed in a much more reader friendly way.

You would suggest that I add a boolean field to a structure to
indicate whether an override mode is present?

A simple  bool has_override = panel->override_mode.type != 0;
would do the trick here.
Then there is no hidden conversion from int to a bool.

But as override_mode can be NULL something more needs to be done.

	Sam
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