Re: [PATCH 7/8] drm/i915/backlight: Provide clear description on how backlight level is controlled

[Murthy, Arun R]

On 24-02-2026 08:50, Kandpal, Suraj wrote:
Subject: Re: [PATCH 7/8] drm/i915/backlight: Provide clear description on how
backlight level is controlled
On 20-02-2026 10:32, Suraj Kandpal wrote:
Currently it takes us multiple log prints to arrive at the conclusion
on how we are actually controlling backlight level. Make the logging
concise.

Signed-off-by: Suraj Kandpal <suraj.kand...@intel.com>
---
   .../drm/i915/display/intel_dp_aux_backlight.c | 19 ++++++++++++++-----
   1 file changed, 14 insertions(+), 5 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 043c9aef2ea6..aac6cdb5b69b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -368,6 +368,16 @@ static const char *dpcd_vs_pwm_str(bool aux)
        return aux ? "DPCD" : "PWM";
   }

+static const char *backlight_unit_str(struct intel_panel *panel) {
+       if (panel->backlight.edp.vesa.info.luminance_set)
+               return "NITS";
+       else if (panel->backlight.edp.vesa.info.aux_set)
+               return "Brightness %";
Should this be AUX Brightness?
So that it calls out its AUX based DPCD backlight control.
Actually where this is called has the line
"AUX VESA backlight level is controlled through %s using %s values\n"
Here we return the unit value we use to control brightness

Sorry missed that, so with having AUX backlight already, this proposed 
change doesnt make much sense.

Reviewed-by: Arun R Murthy <arun.r.mur...@intel.com>

Thanks and Regards,
Arun R Murthy
-------------------

Regards,
Suraj Kandpal

+       else
+               return "PWM";
+}
+
   static void
   intel_dp_aux_write_panel_luminance_override(struct intel_connector
*connector)
   {
@@ -542,9 +552,11 @@ static int
intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector,
                    dpcd_vs_pwm_str(panel-
backlight.edp.vesa.info.aux_enable ||
                                    panel-
backlight.edp.vesa.info.luminance_set));
        drm_dbg_kms(display->drm,
-                   "[CONNECTOR:%d:%s] AUX VESA backlight level is
controlled through %s\n",
+                   "[CONNECTOR:%d:%s] AUX VESA backlight level is
controlled
+through %s using %s values\n",
                    connector->base.base.id, connector->base.name,
-                   dpcd_vs_pwm_str(panel-
backlight.edp.vesa.info.aux_set));
+                   dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_set
||
+                                   panel-
backlight.edp.vesa.info.luminance_set),
+                   backlight_unit_str(panel));

        if (!panel->backlight.edp.vesa.info.aux_set ||
            !panel->backlight.edp.vesa.info.aux_enable) { @@ -569,9 +581,6
@@ static int intel_dp_aux_vesa_setup_backlight(struct intel_connector
*connector,
                panel->backlight.enabled = panel->backlight.level != 0;
                if (!panel->backlight.level)
                        panel->backlight.level = panel->backlight.max;
-               drm_dbg_kms(display->drm,
-                           "[CONNECTOR:%d:%s] AUX VESA Nits backlight
level is controlled through DPCD\n",
-                           connector->base.base.id, connector->base.name);
        } else if (panel->backlight.edp.vesa.info.aux_set) {
                panel->backlight.max = panel->backlight.edp.vesa.info.max;
                panel->backlight.min = 0;