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From:   Qiu Wenbo <qiuwenbo@phytium.com.cn>
To:     Evan Quan <evan.quan@amd.com>, amd-gfx@lists.freedesktop.org
Cc:     Qiu Wenbo <qiuwenbo@phytium.com.cn>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        "David (ChunMing) Zhou" <David1.Zhou@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Chen Wandun <chenwandun@huawei.com>,
        YueHaibing <yuehaibing@huawei.com>, yu kuai <yukuai3@huawei.com>,
        Eric Huang <JinHuiEric.Huang@amd.com>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH] drm/amd/powerplay: fix a crash when overclocking Vega M
Date:   Fri, 17 Jul 2020 15:09:57 +0800
Message-Id: <20200717070958.41489-1-qiuwenbo@phytium.com.cn>
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Sender: linux-kernel-owner@vger.kernel.org
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Avoid kernel crash when vddci_control is SMU7_VOLTAGE_CONTROL_NONE and
vddci_voltage_table is empty. It has been tested on Intel Hades Canyon
(i7-8809G).

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=208489
Fixes: ac7822b0026f ("drm/amd/powerplay: add smumgr support for VEGAM (v2)")
Signed-off-by: Qiu Wenbo <qiuwenbo@phytium.com.cn>
---
 drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c b/drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c
index 3da71a088b92..0ecc18b55ffb 100644
--- a/drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c
+++ b/drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c
@@ -644,9 +644,6 @@ static int vegam_get_dependency_volt_by_clk(struct pp_hwmgr *hwmgr,
 
 	/* sclk is bigger than max sclk in the dependence table */
 	*voltage |= (dep_table->entries[i - 1].vddc * VOLTAGE_SCALE) << VDDC_SHIFT;
-	vddci = phm_find_closest_vddci(&(data->vddci_voltage_table),
-			(dep_table->entries[i - 1].vddc -
-					(uint16_t)VDDC_VDDCI_DELTA));
 
 	if (SMU7_VOLTAGE_CONTROL_NONE == data->vddci_control)
 		*voltage |= (data->vbios_boot_state.vddci_bootup_value *
@@ -654,8 +651,13 @@ static int vegam_get_dependency_volt_by_clk(struct pp_hwmgr *hwmgr,
 	else if (dep_table->entries[i - 1].vddci)
 		*voltage |= (dep_table->entries[i - 1].vddci *
 				VOLTAGE_SCALE) << VDDC_SHIFT;
-	else
+	else {
+		vddci = phm_find_closest_vddci(&(data->vddci_voltage_table),
+				(dep_table->entries[i - 1].vddc -
+						(uint16_t)VDDC_VDDCI_DELTA));
+
 		*voltage |= (vddci * VOLTAGE_SCALE) << VDDCI_SHIFT;
+	}
 
 	if (SMU7_VOLTAGE_CONTROL_NONE == data->mvdd_control)
 		*mvdd = data->vbios_boot_state.mvdd_bootup_value * VOLTAGE_SCALE;
-- 
2.27.0