Nouveau Archive on lore.kernel.org
 help / color / Atom feed
From: Lyude Paul <lyude@redhat.com>
To: dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
	intel-gfx@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	open list <linux-kernel@vger.kernel.org>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Sean Paul <seanpaul@chromium.org>,
	Daniel Vetter <daniel@ffwll.ch>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: [Nouveau] [RFC v3 04/10] drm/i915/dpcd_bl: Handle drm_dpcd_read/write() return values correctly
Date: Fri,  5 Feb 2021 18:45:08 -0500
Message-ID: <20210205234515.1216538-5-lyude@redhat.com> (raw)
In-Reply-To: <20210205234515.1216538-1-lyude@redhat.com>

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>
---
 .../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 62294967f430..c37ccc8538cb 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,
-			      &reg_val) < 0) {
+	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);
 		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;
-- 
2.29.2

_______________________________________________
Nouveau mailing list
Nouveau@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/nouveau

  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-05 23:45 [Nouveau] [RFC v3 00/10] drm: Extract DPCD backlight helpers from i915, add support in nouveau Lyude Paul
2021-02-05 23:45 ` [Nouveau] [RFC v3 01/10] drm/nouveau/kms/nv40-/backlight: Assign prop type once Lyude Paul
2021-02-05 23:45 ` [Nouveau] [RFC v3 02/10] drm/nouveau/kms: Don't probe eDP connectors more then once Lyude Paul
2021-02-05 23:45 ` [Nouveau] [RFC v3 03/10] drm/i915/dpcd_bl: Remove redundant AUX backlight frequency calculations Lyude Paul
2021-02-05 23:45 ` Lyude Paul [this message]
2021-02-08 11:11   ` [Nouveau] [RFC v3 04/10] drm/i915/dpcd_bl: Handle drm_dpcd_read/write() return values correctly Rodrigo Vivi
2021-02-05 23:45 ` [Nouveau] [RFC v3 05/10] drm/i915/dpcd_bl: Cleanup intel_dp_aux_vesa_enable_backlight() a bit Lyude Paul
2021-02-06  0:07   ` Ilia Mirkin
2021-02-05 23:45 ` [Nouveau] [RFC v3 06/10] drm/i915/dpcd_bl: Cache some backlight capabilities in intel_panel.backlight Lyude Paul
2021-02-08 11:13   ` Rodrigo Vivi
2021-02-05 23:45 ` [Nouveau] [RFC v3 07/10] drm/i915/dpcd_bl: Move VESA backlight enabling code closer together Lyude Paul
2021-02-08 11:14   ` Rodrigo Vivi
2021-02-05 23:45 ` [Nouveau] [RFC v3 08/10] drm/i915/dpcd_bl: Return early in vesa_calc_max_backlight if we can't read PWMGEN_BIT_COUNT Lyude Paul
2021-02-05 23:45 ` [Nouveau] [RFC v3 09/10] drm/i915/dpcd_bl: Print return codes for VESA backlight failures Lyude Paul
2021-02-05 23:45 ` [Nouveau] [RFC v3 10/10] drm/dp: Extract i915's eDP backlight code into DRM helpers Lyude Paul
2021-02-08  8:46   ` Thomas Zimmermann
2021-02-08 23:03     ` Lyude Paul
2021-02-15 18:34       ` Thomas Zimmermann
2021-02-15 20:26         ` Lyude Paul
2021-02-08 22:52 ` [Nouveau] [RFC v3 00/10] drm: Extract DPCD backlight helpers from i915, add support in nouveau Lyude Paul

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210205234515.1216538-5-lyude@redhat.com \
    --to=lyude@redhat.com \
    --cc=airlied@linux.ie \
    --cc=daniel@ffwll.ch \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=jani.nikula@linux.intel.com \
    --cc=joonas.lahtinen@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=nouveau@lists.freedesktop.org \
    --cc=rodrigo.vivi@intel.com \
    --cc=seanpaul@chromium.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Nouveau Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/nouveau/0 nouveau/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 nouveau nouveau/ https://lore.kernel.org/nouveau \
		nouveau@lists.freedesktop.org
	public-inbox-index nouveau

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.freedesktop.lists.nouveau


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git