[PATCH] drm/amd/powerplay: fix a crash when overclocking Vega M

[Quan, Evan]

[AMD Official Use Only - Internal Distribution Only]

Reviewed-by: Evan Quan <evan.quan at amd.com>

-----Original Message-----
From: Qiu Wenbo <qiuwenbo at phytium.com.cn>
Sent: Friday, July 17, 2020 3:10 PM
To: Quan, Evan <Evan.Quan at amd.com>; amd-gfx at lists.freedesktop.org
Cc: Qiu Wenbo <qiuwenbo at phytium.com.cn>; Deucher, Alexander <Alexander.Deucher at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Zhou, David(ChunMing) <David1.Zhou at amd.com>; David Airlie <airlied at linux.ie>; Daniel Vetter <daniel at ffwll.ch>; Chen Wandun <chenwandun at huawei.com>; YueHaibing <yuehaibing at huawei.com>; yu kuai <yukuai3 at huawei.com>; Huang, JinHuiEric <JinHuiEric.Huang at amd.com>; dri-devel at lists.freedesktop.org; linux-kernel at vger.kernel.org
Subject: [PATCH] drm/amd/powerplay: fix a crash when overclocking Vega M

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://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.kernel.org%2Fshow_bug.cgi%3Fid%3D208489&data=02%7C01%7Cevan.quan%40amd.com%7Cff6bf841473b46539e1708d82a20723d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637305666456662890&sdata=%2FMXKE9MMkUF2JPR3JiCTNdgAyyRnQXkxpZfS9eTPrW8%3D&reserved=0
Fixes: ac7822b0026f ("drm/amd/powerplay: add smumgr support for VEGAM (v2)")
Signed-off-by: Qiu Wenbo <qiuwenbo at 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