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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Stephen Boyd <swboyd@chromium.org>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	Bjorn Andersson <andersson@kernel.org>,
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org
Subject: [PATCH] drm/msm/dsi: properly handle the case of empty OPP table in dsi_mgr_bridge_mode_valid
Date: Tue, 24 Jan 2023 22:36:00 +0200	[thread overview]
Message-ID: <20230124203600.3488766-1-dmitry.baryshkov@linaro.org> (raw)

It was left unnoticed during the review that even if there is no OPP
table in device tree, one will be created by a call to the function
devm_pm_opp_set_clkname(). This leads to dsi_mgr_bridge_mode_valid()
rejecting all modes if DT contains no OPP table for the DSI host.

Rework dsi_mgr_bridge_mode_valid() to handle this case by actually
checking that the table is populated with frequency entries before
returning an error.

Fixes: 8328041b8c82 ("drm/msm/dsi: implement opp table based check for dsi_mgr_bridge_mode_valid()")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/msm/dsi/dsi_manager.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index b20fddb534a7..1bbac72dad35 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
@@ -456,18 +456,19 @@ static enum drm_mode_status dsi_mgr_bridge_mode_valid(struct drm_bridge *bridge,
 
 	byte_clk_rate = dsi_byte_clk_get_rate(host, IS_BONDED_DSI(), mode);
 
-	/*
-	 * fail all errors except -ENODEV as that could mean that opp
-	 * table is not yet implemented
-	 */
 	opp = dev_pm_opp_find_freq_ceil(&pdev->dev, &byte_clk_rate);
-	if (IS_ERR(opp)) {
-		if (PTR_ERR(opp) == -ERANGE)
+	if (!IS_ERR(opp)) {
+		dev_pm_opp_put(opp);
+	} else if (PTR_ERR(opp) == -ERANGE) {
+		/*
+		 * An empty table is created by devm_pm_opp_set_clkname() even
+		 * if there is none. Thus find_freq_ceil will still return
+		 * -ERANGE in such case.
+		 */
+		if (dev_pm_opp_get_opp_count(&pdev->dev) != 0)
 			return MODE_CLOCK_RANGE;
-		else if (PTR_ERR(opp) != -ENODEV)
-			return MODE_ERROR;
 	} else {
-		dev_pm_opp_put(opp);
+			return MODE_ERROR;
 	}
 
 	return msm_dsi_host_check_dsc(host, mode);
-- 
2.39.0


WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
	Bjorn Andersson <andersson@kernel.org>,
	dri-devel@lists.freedesktop.org,
	Stephen Boyd <swboyd@chromium.org>
Subject: [PATCH] drm/msm/dsi: properly handle the case of empty OPP table in dsi_mgr_bridge_mode_valid
Date: Tue, 24 Jan 2023 22:36:00 +0200	[thread overview]
Message-ID: <20230124203600.3488766-1-dmitry.baryshkov@linaro.org> (raw)

It was left unnoticed during the review that even if there is no OPP
table in device tree, one will be created by a call to the function
devm_pm_opp_set_clkname(). This leads to dsi_mgr_bridge_mode_valid()
rejecting all modes if DT contains no OPP table for the DSI host.

Rework dsi_mgr_bridge_mode_valid() to handle this case by actually
checking that the table is populated with frequency entries before
returning an error.

Fixes: 8328041b8c82 ("drm/msm/dsi: implement opp table based check for dsi_mgr_bridge_mode_valid()")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/msm/dsi/dsi_manager.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index b20fddb534a7..1bbac72dad35 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
@@ -456,18 +456,19 @@ static enum drm_mode_status dsi_mgr_bridge_mode_valid(struct drm_bridge *bridge,
 
 	byte_clk_rate = dsi_byte_clk_get_rate(host, IS_BONDED_DSI(), mode);
 
-	/*
-	 * fail all errors except -ENODEV as that could mean that opp
-	 * table is not yet implemented
-	 */
 	opp = dev_pm_opp_find_freq_ceil(&pdev->dev, &byte_clk_rate);
-	if (IS_ERR(opp)) {
-		if (PTR_ERR(opp) == -ERANGE)
+	if (!IS_ERR(opp)) {
+		dev_pm_opp_put(opp);
+	} else if (PTR_ERR(opp) == -ERANGE) {
+		/*
+		 * An empty table is created by devm_pm_opp_set_clkname() even
+		 * if there is none. Thus find_freq_ceil will still return
+		 * -ERANGE in such case.
+		 */
+		if (dev_pm_opp_get_opp_count(&pdev->dev) != 0)
 			return MODE_CLOCK_RANGE;
-		else if (PTR_ERR(opp) != -ENODEV)
-			return MODE_ERROR;
 	} else {
-		dev_pm_opp_put(opp);
+			return MODE_ERROR;
 	}
 
 	return msm_dsi_host_check_dsc(host, mode);
-- 
2.39.0


             reply	other threads:[~2023-01-24 20:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-24 20:36 Dmitry Baryshkov [this message]
2023-01-24 20:36 ` [PATCH] drm/msm/dsi: properly handle the case of empty OPP table in dsi_mgr_bridge_mode_valid Dmitry Baryshkov
2023-01-24 20:49 ` Abhinav Kumar
2023-01-24 20:49   ` Abhinav Kumar
2023-01-26 19:00 ` Dmitry Baryshkov
2023-01-26 19:00   ` Dmitry Baryshkov

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