From 373fdcce4d1abedc1ad47312cd248913900c7416 Mon Sep 17 00:00:00 2001
From: Lyude Paul <lyude@redhat.com>
Date: Fri, 14 May 2021 14:14:56 -0400
Subject: drm/i915/dpcd_bl: Handle drm_dpcd_read/write() return values
correctly
Git-commit: 3faea9939a3d1eb5a40f3f6100c24792865b6445
Patch-mainline: v5.15-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
This is kind of an annoying aspect of DRM's DP helpers:
drm_dp_dpcd_readb/writeb() return the size of bytes read/written on
success, thus we want to check against that instead of checking if the
return value is less than 0.
I'll probably be fixing this in the near future once I start doing DP work
again, also because I'd rather not mix a tree-wide refactor like that in
with a patch series intended to be around introducing DP backlight helpers.
So, for now let's just handle the return values from each function
correctly.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210514181504.565252-3-lyude@redhat.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
.../drm/i915/display/intel_dp_aux_backlight.c | 41 +++++++++----------
1 file changed, 19 insertions(+), 22 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 68bfe50ada59..1dbe38282ebe 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -107,7 +107,7 @@ intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
u8 tcon_cap[4];
ret = drm_dp_dpcd_read(aux, INTEL_EDP_HDR_TCON_CAP0, tcon_cap, sizeof(tcon_cap));
- if (ret < 0)
+ if (ret != sizeof(tcon_cap))
return false;
if (!(tcon_cap[1] & INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP))
@@ -137,7 +137,7 @@ intel_dp_aux_hdr_get_backlight(struct intel_connector *connector, enum pipe pipe
u8 tmp;
u8 buf[2] = { 0 };
- if (drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &tmp) < 0) {
+ if (drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &tmp) != 1) {
drm_err(&i915->drm, "Failed to read current backlight mode from DPCD\n");
return 0;
}
@@ -153,7 +153,8 @@ intel_dp_aux_hdr_get_backlight(struct intel_connector *connector, enum pipe pipe
return panel->backlight.max;
}
- if (drm_dp_dpcd_read(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf, sizeof(buf)) < 0) {
+ if (drm_dp_dpcd_read(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf,
+ sizeof(buf)) != sizeof(buf)) {
drm_err(&i915->drm, "Failed to read brightness from DPCD\n");
return 0;
}
@@ -172,7 +173,8 @@ intel_dp_aux_hdr_set_aux_backlight(const struct drm_connector_state *conn_state,
buf[0] = level & 0xFF;
buf[1] = (level & 0xFF00) >> 8;
- if (drm_dp_dpcd_write(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf, 4) < 0)
+ if (drm_dp_dpcd_write(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf,
+ sizeof(buf)) != sizeof(buf))
drm_err(dev, "Failed to write brightness level to DPCD\n");
}
@@ -203,7 +205,7 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
u8 old_ctrl, ctrl;
ret = drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &old_ctrl);
- if (ret < 0) {
+ if (ret != 1) {
drm_err(&i915->drm, "Failed to read current backlight control mode: %d\n", ret);
return;
}
@@ -221,7 +223,7 @@ intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
}
if (ctrl != old_ctrl)
- if (drm_dp_dpcd_writeb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, ctrl) < 0)
+ if (drm_dp_dpcd_writeb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, ctrl) != 1)
drm_err(&i915->drm, "Failed to configure DPCD brightness controls\n");
}
@@ -277,8 +279,7 @@ static void set_vesa_backlight_enable(struct intel_dp *intel_dp, bool enable)
if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP))
return;
- if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
- ®_val) < 0) {
+ if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, ®_val) != 1) {
drm_dbg_kms(&i915->drm, "Failed to read DPCD register 0x%x\n",
DP_EDP_DISPLAY_CONTROL_REGISTER);
return;
@@ -332,8 +333,8 @@ 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)) < 0) {
+ 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);
return 0;
@@ -365,8 +366,8 @@ intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state,
vals[0] = (level & 0xFF00) >> 8;
vals[1] = (level & 0xFF);
}
- if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
- vals, sizeof(vals)) < 0) {
+ 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");
return;
@@ -401,9 +402,8 @@ 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) < 0)
+ 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");
@@ -424,11 +424,9 @@ intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state,
}
if (new_dpcd_buf != dpcd_buf) {
- if (drm_dp_dpcd_writeb(&intel_dp->aux,
- DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf) < 0) {
- drm_dbg_kms(&i915->drm,
- "Failed to write aux backlight mode\n");
- }
+ 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");
}
intel_dp_aux_vesa_set_backlight(conn_state, level);
@@ -519,8 +517,7 @@ 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) < 0) {
+ 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");
return max_backlight;
--
2.38.1