Merge tag 'drm-misc-next-2025-10-02' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next

drm-misc-next for v6.19:

UAPI Changes:

Cross-subsystem Changes:
-  fbcon cleanups.
- Make drivers depend on FB_TILEBLITTING instead of selecting it,
  and hide FB_MODE_HELPERS.

Core Changes:
- More preparations for rust.
- Throttle dirty worker with vblank
- Use drm_for_each_bridge_in_chain_scoped in drm's bridge code and
  assorted fixes.
- Ensure drm_client_modeset tests are enabled in UML.
- Rename ttm_bo_put to ttm_bo_fini, as a further step in removing the
  TTM bo refcount.
- Add POST_LT_ADJ_REQ training sequence.
- Show list of removed but still allocated bridges.
- Add a simulated vblank interrupt for hardware without it,
  and add some helpers to use them in vkms and hypervdrm.

Driver Changes:
- Assorted small fixes, cleanups and updates to host1x, tegra,
  panthor,   amdxdna, gud, vc4, ssd130x, ivpu, panfrost, panthor,
  sysfb, bridge/sn65dsi86, solomon, ast, tidss.
- Convert drivers from using .round_rate() to .determine_rate()
- Add support for KD116N3730A07/A12, chromebook mt8189, JT101TM023,
  LQ079L1SX01, raspberrypi 5" panels.
- Improve reclocking on tegra186+ with nouveau.
- Improve runtime pm in amdxdna.
- Add support for HTX_PAI in imx.
- Use a helper to calculate dumb buffer sizes in most drivers.

Signed-off-by: Simona Vetter <simona.vetter@ffwll.ch>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://lore.kernel.org/r/b412fb91-8545-466a-8102-d89c0f2758a7@linux.intel.com

1 files changed, 57 insertions, 19 deletions

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 4aaeae4fa03c..49803528023b 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -29,6 +29,7 @@
 #include <linux/init.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
@@ -123,6 +124,14 @@ bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
 }
 EXPORT_SYMBOL(drm_dp_clock_recovery_ok);
 
+bool drm_dp_post_lt_adj_req_in_progress(const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+	u8 lane_align = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED);
+
+	return lane_align & DP_POST_LT_ADJ_REQ_IN_PROGRESS;
+}
+EXPORT_SYMBOL(drm_dp_post_lt_adj_req_in_progress);
+
 u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE],
 				     int lane)
 {
@@ -4128,22 +4137,61 @@ drm_edp_backlight_probe_max(struct drm_dp_aux *aux, struct drm_edp_backlight_inf
 {
 	int fxp, fxp_min, fxp_max, fxp_actual, f = 1;
 	int ret;
-	u8 pn, pn_min, pn_max;
+	u8 pn, pn_min, pn_max, bit_count;
 
 	if (!bl->aux_set)
 		return 0;
 
-	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_PWMGEN_BIT_COUNT, &pn);
+	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_PWMGEN_BIT_COUNT, &bit_count);
 	if (ret < 0) {
 		drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap: %d\n",
 			    aux->name, ret);
 		return -ENODEV;
 	}
 
-	pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
+	bit_count &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
+
+	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min);
+	if (ret < 0) {
+		drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap min: %d\n",
+			    aux->name, ret);
+		return -ENODEV;
+	}
+	pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
+
+	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max);
+	if (ret < 0) {
+		drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap max: %d\n",
+			    aux->name, ret);
+		return -ENODEV;
+	}
+	pn_max &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
+
+	if (unlikely(pn_min > pn_max)) {
+		drm_dbg_kms(aux->drm_dev, "%s: Invalid pwmgen bit count cap min/max returned: %d %d\n",
+			    aux->name, pn_min, pn_max);
+		return -EINVAL;
+	}
+
+	/*
+	 * Per VESA eDP Spec v1.4b, section 3.3.10.2:
+	 * If DP_EDP_PWMGEN_BIT_COUNT is less than DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN,
+	 * the sink must use the MIN value as the effective PWM bit count.
+	 * Clamp the reported value to the [MIN, MAX] capability range to ensure
+	 * correct brightness scaling on compliant eDP panels.
+	 * Only enable this logic if the [MIN, MAX] range is valid in regard to Spec.
+	 */
+	pn = bit_count;
+	if (bit_count < pn_min)
+		pn = clamp(bit_count, pn_min, pn_max);
+
 	bl->max = (1 << pn) - 1;
-	if (!driver_pwm_freq_hz)
+	if (!driver_pwm_freq_hz) {
+		if (pn != bit_count)
+			goto bit_count_write_back;
+
 		return 0;
+	}
 
 	/*
 	 * Set PWM Frequency divider to match desired frequency provided by the driver.
@@ -4167,21 +4215,6 @@ drm_edp_backlight_probe_max(struct drm_dp_aux *aux, struct drm_edp_backlight_inf
 	 * - FxP is within 25% of desired value.
 	 *   Note: 25% is arbitrary value and may need some tweak.
 	 */
-	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min);
-	if (ret < 0) {
-		drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap min: %d\n",
-			    aux->name, ret);
-		return 0;
-	}
-	ret = drm_dp_dpcd_read_byte(aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max);
-	if (ret < 0) {
-		drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap max: %d\n",
-			    aux->name, ret);
-		return 0;
-	}
-	pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
-	pn_max &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
-
 	/* Ensure frequency is within 25% of desired value */
 	fxp_min = DIV_ROUND_CLOSEST(fxp * 3, 4);
 	fxp_max = DIV_ROUND_CLOSEST(fxp * 5, 4);
@@ -4199,12 +4232,17 @@ drm_edp_backlight_probe_max(struct drm_dp_aux *aux, struct drm_edp_backlight_inf
 			break;
 	}
 
+bit_count_write_back:
 	ret = drm_dp_dpcd_write_byte(aux, DP_EDP_PWMGEN_BIT_COUNT, pn);
 	if (ret < 0) {
 		drm_dbg_kms(aux->drm_dev, "%s: Failed to write aux pwmgen bit count: %d\n",
 			    aux->name, ret);
 		return 0;
 	}
+
+	if (!driver_pwm_freq_hz)
+		return 0;
+
 	bl->pwmgen_bit_count = pn;
 	bl->max = (1 << pn) - 1;