Hi,

Am 15.04.25 um 17:48 schrieb Werner Sembach:
Hi,

Am 11.04.25 um 20:56 schrieb Ville Syrjälä:
On Fri, Apr 11, 2025 at 05:55:08PM +0200, Werner Sembach wrote:
The display backlight on TUXEDO DX1708 and InsanityBook 15 v1 with panels
AUO 12701 and AUO 12701 must be forced to INTEL_DP_AUX_BACKLIGHT_ON to be
able to control the brightness.

This could already be archived via a module parameter, but this patch adds
a quirk to apply this by default on the mentioned device + panel
combinations.
Why aren't you fixing the VBT to be correct in the first place?

I don't have access to the firmware source code and these are quite old devices so I also can't request a fix from the ODM. Besides: it can be quite hard to explain to the ODM what exactly the problem is if it doesn't also affect Windows.

TBH I don't know what VBT stands for, I just assumed it has to to with the displays firmware?

Unlike I wrote in the cover letter we actually still had an affected device in our archives -> the issue persists and the quirk is still necessary.

Best Regards,

Werner


Best regards,

Werner Sembach


Signed-off-by: Werner Sembach <w...@tuxedocomputers.com>
Cc: sta...@vger.kernel.org
---
  .../drm/i915/display/intel_dp_aux_backlight.c | 14 ++++++-
  drivers/gpu/drm/i915/display/intel_quirks.c   | 42 +++++++++++++++++++
  drivers/gpu/drm/i915/display/intel_quirks.h   |  1 +
  3 files changed, 56 insertions(+), 1 deletion(-)

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 c846ef4acf5b2..0cac04c98a3e3 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -34,12 +34,14 @@
   * for some reason.
   */
  +#include <drm/drm_edid.h>
  #include "i915_utils.h"
  #include "intel_backlight.h"
  #include "intel_display_core.h"
  #include "intel_display_types.h"
  #include "intel_dp.h"
  #include "intel_dp_aux_backlight.h"
+#include "intel_quirks.h"
    /*
   * DP AUX registers for Intel's proprietary HDR backlight interface. We define @@ -607,11 +609,21 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
      struct drm_device *dev = connector->base.dev;
      struct intel_panel *panel = &connector->panel;
      bool try_intel_interface = false, try_vesa_interface = false;
+    int enable_dpcd_backlight;
+    u32 pnl_id;
        /* Check the VBT and user's module parameters to figure out which
       * interfaces to probe
       */
-    switch (display->params.enable_dpcd_backlight) {
+    enable_dpcd_backlight = display->params.enable_dpcd_backlight;
+    if (enable_dpcd_backlight == INTEL_DP_AUX_BACKLIGHT_AUTO &&
+        intel_has_quirk(display, QUIRK_AUO_12701_21229_ENABLE_DPCD_BACKLIGHT)) {
+        pnl_id = drm_edid_get_panel_id(panel->fixed_edid);
+        if (pnl_id == drm_edid_encode_panel_id('A', 'U', 'O', 0x319d) ||
+            pnl_id == drm_edid_encode_panel_id('A', 'U', 'O', 0x52ed))
+            enable_dpcd_backlight = INTEL_DP_AUX_BACKLIGHT_ON;
+    }
+    switch (enable_dpcd_backlight) {
      case INTEL_DP_AUX_BACKLIGHT_OFF:
          return -ENODEV;
      case INTEL_DP_AUX_BACKLIGHT_AUTO:
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c
index 8b30e9fd936e7..6f724e5712664 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.c
+++ b/drivers/gpu/drm/i915/display/intel_quirks.c
@@ -78,6 +78,12 @@ static void quirk_fw_sync_len(struct intel_dp *intel_dp)
      drm_info(display->drm, "Applying Fast Wake sync pulse count quirk\n");
  }
  +static void quirk_auo_12701_21229_enable_dpcd_backlight(struct intel_display *display)
+{
+    intel_set_quirk(display, QUIRK_AUO_12701_21229_ENABLE_DPCD_BACKLIGHT);
+    drm_info(display->drm, "Applying Display AUO Model 12701 and 21229 Enable DPCD Backlight quirk\n");
+}
+
  struct intel_quirk {
      int device;
      int subsystem_vendor;
@@ -118,6 +124,12 @@ static int intel_dmi_no_pps_backlight(const struct dmi_system_id *id)
      return 1;
  }
  +static int intel_dmi_auo_12701_21229_enable_dpcd_backlight(const struct dmi_system_id *id)
+{
+    DRM_INFO("Display AUO model 12701 and 21229 DPCD backlight control on %s\n", id->ident);
+    return 1;
+}
+
  static const struct intel_dmi_quirk intel_dmi_quirks[] = {
      {
          .dmi_id_list = &(const struct dmi_system_id[]) {
@@ -164,6 +176,36 @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = {
          },
          .hook = quirk_no_pps_backlight_power_hook,
      },
+    {
+        .dmi_id_list = &(const struct dmi_system_id[]) {
+            {
+                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
+                .ident = "TUXEDO DX1708",
+                .matches = {DMI_MATCH(DMI_BOARD_NAME, "N8xEJEK"),
+                },
+            },
+            {
+                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
+                .ident = "TUXEDO InsanityBook 15 v1",
+                .matches = {DMI_MATCH(DMI_BOARD_NAME, "P95_HP"),
+                },
+            },
+            {
+                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
+                .ident = "TUXEDO InsanityBook 15 v1",
+                .matches = {DMI_MATCH(DMI_BOARD_NAME, "P95_HR"),
+                },
+            },
+            {
+                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
+                .ident = "TUXEDO InsanityBook 15 v1",
+                .matches = {DMI_MATCH(DMI_BOARD_NAME, "P95_HP,HR,HQ"),
+                },
+            },
+            { }
+        },
+        .hook = quirk_auo_12701_21229_enable_dpcd_backlight,
+    },
  };
    static struct intel_quirk intel_quirks[] = {
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.h b/drivers/gpu/drm/i915/display/intel_quirks.h
index cafdebda75354..38bdbd65d7efb 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.h
+++ b/drivers/gpu/drm/i915/display/intel_quirks.h
@@ -20,6 +20,7 @@ enum intel_quirk_id {
      QUIRK_LVDS_SSC_DISABLE,
      QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK,
      QUIRK_FW_SYNC_LEN,
+    QUIRK_AUO_12701_21229_ENABLE_DPCD_BACKLIGHT,
  };
    void intel_init_quirks(struct intel_display *display);
--
2.43.0

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