Re: [Intel-gfx] [RFC v4 09/11] drm/i915/dpcd_bl: Print return codes for VESA backlight failures

From: Rodrigo Vivi
Date: Wed Feb 10 2021 - 22:48:32 EST

On Mon, Feb 08, 2021 at 06:38:59PM -0500, Lyude Paul wrote:
> Also, stop printing the DPCD register that failed, and just describe it
> instead. Saves us from having to look up each register offset when reading
> through kernel logs (plus, DPCD dumping with drm.debug |= 0x100 will give
> us that anyway).
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>

> ---
> .../drm/i915/display/intel_dp_aux_backlight.c | 101 +++++++++---------
> 1 file changed, 52 insertions(+), 49 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 a139f0e08839..a98d9bd4b0ed 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -274,14 +274,12 @@ static bool intel_dp_aux_vesa_backlight_dpcd_mode(struct intel_connector *connec
> {
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + int ret;
> u8 mode_reg;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux,
> - DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
> - &mode_reg) != 1) {
> - drm_dbg_kms(&i915->drm,
> - "Failed to read the DPCD register 0x%x\n",
> - DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
> + ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &mode_reg);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to read backlight mode: %d\n", ret);
> return false;
> }
>
> @@ -297,6 +295,7 @@ static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, en
> {
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + int ret;
> u8 read_val[2] = { 0x0 };
> u16 level = 0;
>
> @@ -307,10 +306,10 @@ static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, en
> if (!intel_dp_aux_vesa_backlight_dpcd_mode(connector))
> return connector->panel.backlight.max;
>
> - if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, &read_val,
> - sizeof(read_val)) != sizeof(read_val)) {
> - drm_dbg_kms(&i915->drm, "Failed to read DPCD register 0x%x\n",
> - DP_EDP_BACKLIGHT_BRIGHTNESS_MSB);
> + ret = drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, &read_val,
> + sizeof(read_val));
> + if (ret != sizeof(read_val)) {
> + drm_dbg_kms(&i915->drm, "Failed to read brightness level: %d\n", ret);
> return 0;
> }
>
> @@ -333,6 +332,7 @@ intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state,
> struct intel_connector *connector = to_intel_connector(conn_state->connector);
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + int ret;
> u8 vals[2] = { 0x0 };
>
> /* Write the MSB and/or LSB */
> @@ -343,10 +343,10 @@ intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state,
> vals[0] = level;
> }
>
> - if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, vals,
> - sizeof(vals)) != sizeof(vals)) {
> - drm_dbg_kms(&i915->drm,
> - "Failed to write aux backlight level\n");
> + ret = drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, vals,
> + sizeof(vals));
> + if (ret != sizeof(vals)) {
> + drm_dbg_kms(&i915->drm, "Failed to write aux backlight level: %d\n", ret);
> return;
> }
> }
> @@ -355,26 +355,28 @@ static void set_vesa_backlight_enable(struct intel_connector *connector, bool en
> {
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + int ret;
> u8 reg_val = 0;
>
> /* Early return when display use other mechanism to enable backlight. */
> if (!connector->panel.backlight.edp.vesa.aux_enable)
> return;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, &reg_val) != 1) {
> - drm_dbg_kms(&i915->drm, "Failed to read DPCD register 0x%x\n",
> - DP_EDP_DISPLAY_CONTROL_REGISTER);
> + ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, &reg_val);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to read eDP display control register: %d\n", ret);
> return;
> }
> +
> if (enable)
> reg_val |= DP_EDP_BACKLIGHT_ENABLE;
> else
> reg_val &= ~(DP_EDP_BACKLIGHT_ENABLE);
>
> - if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
> - reg_val) != 1) {
> - drm_dbg_kms(&i915->drm, "Failed to %s aux backlight\n",
> - enable ? "enable" : "disable");
> + ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, reg_val);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to %s aux backlight: %d\n",
> + enable ? "enable" : "disable", ret);
> }
> }
>
> @@ -386,13 +388,13 @@ intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state,
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> struct intel_panel *panel = &connector->panel;
> + int ret;
> u8 dpcd_buf, new_dpcd_buf;
> u8 pwmgen_bit_count = panel->backlight.edp.vesa.pwmgen_bit_count;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux,
> - DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) {
> - drm_dbg_kms(&i915->drm, "Failed to read DPCD register 0x%x\n",
> - DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
> + ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to read backlight mode: %d\n", ret);
> return;
> }
>
> @@ -402,24 +404,26 @@ intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state,
> new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
>
> - if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT,
> - pwmgen_bit_count) != 1)
> - drm_dbg_kms(&i915->drm,
> - "Failed to write aux pwmgen bit count\n");
> + ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, pwmgen_bit_count);
> + if (ret != 1)
> + drm_dbg_kms(&i915->drm, "Failed to write aux pwmgen bit count: %d\n", ret);
> }
>
> if (panel->backlight.edp.vesa.pwm_freq_pre_divider) {
> - if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_FREQ_SET,
> - panel->backlight.edp.vesa.pwm_freq_pre_divider) == 1)
> + ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_FREQ_SET,
> + panel->backlight.edp.vesa.pwm_freq_pre_divider);
> + if (ret == 1)
> new_dpcd_buf |= DP_EDP_BACKLIGHT_FREQ_AUX_SET_ENABLE;
> else
> - drm_dbg_kms(&i915->drm, "Failed to write aux backlight frequency\n");
> + drm_dbg_kms(&i915->drm, "Failed to write aux backlight frequency: %d\n",
> + ret);
> }
>
> if (new_dpcd_buf != dpcd_buf) {
> - if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
> - new_dpcd_buf) != 1)
> - drm_dbg_kms(&i915->drm, "Failed to write aux backlight mode\n");
> + ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
> + new_dpcd_buf);
> + if (ret != 1)
> + drm_dbg_kms(&i915->drm, "Failed to write aux backlight mode: %d\n", ret);
> }
>
> intel_dp_aux_vesa_set_backlight(conn_state, level);
> @@ -446,11 +450,12 @@ static u32 intel_dp_aux_vesa_calc_max_backlight(struct intel_connector *connecto
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> struct intel_panel *panel = &connector->panel;
> u32 max_backlight = 0;
> - int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1;
> + int ret, freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1;
> u8 pn, pn_min, pn_max;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) != 1) {
> - drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap\n");
> + ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap: %d\n", ret);
> return 0;
> }
>
> @@ -479,16 +484,14 @@ static u32 intel_dp_aux_vesa_calc_max_backlight(struct intel_connector *connecto
> * - FxP is within 25% of desired value.
> * Note: 25% is arbitrary value and may need some tweak.
> */
> - if (drm_dp_dpcd_readb(&intel_dp->aux,
> - DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min) != 1) {
> - drm_dbg_kms(&i915->drm,
> - "Failed to read pwmgen bit count cap min\n");
> + ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap min: %d\n", ret);
> return max_backlight;
> }
> - if (drm_dp_dpcd_readb(&intel_dp->aux,
> - DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max) != 1) {
> - drm_dbg_kms(&i915->drm,
> - "Failed to read pwmgen bit count cap max\n");
> + ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap max: %d\n", ret);
> return max_backlight;
> }
> pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
> @@ -512,9 +515,9 @@ static u32 intel_dp_aux_vesa_calc_max_backlight(struct intel_connector *connecto
> }
>
> drm_dbg_kms(&i915->drm, "Using eDP pwmgen bit count of %d\n", pn);
> - if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, pn) != 1) {
> - drm_dbg_kms(&i915->drm,
> - "Failed to write aux pwmgen bit count\n");
> + ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, pn);
> + if (ret != 1) {
> + drm_dbg_kms(&i915->drm, "Failed to write aux pwmgen bit count: %d\n", ret);
> return max_backlight;
> }
>
> --
> 2.29.2
>
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