[PATCH 5.12 165/242] drm/amdgpu: fix the hang caused by PCIe link width switch

Greg Kroah-Hartman
2021-07-15T19:18:50Z

From: Evan Quan <evan.quan@amd.com>

commit adcf949e664a8b04df2fb8aa916892e58561653c upstream.

SMU had set all the necessary fields for a link width switch
but the width switch wasn't occurring because the link was idle
in the L1 state. Setting LC_L1_RECONFIG_EN=0x1 will allow width
switches to also be initiated while in L1 instead of waiting until
the link is back in L0.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.h | 1 +
drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c | 13 +++++++++++++
drivers/gpu/drm/amd/amdgpu/nv.c | 3 +++
3 files changed, 17 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.h
@@ -90,6 +90,7 @@ struct amdgpu_nbio_funcs {
bool enable);
void (*program_aspm)(struct amdgpu_device *adev);
void (*apply_lc_spc_mode_wa)(struct amdgpu_device *adev);
+ void (*apply_l1_link_width_reconfig_wa)(struct amdgpu_device *adev);
};

struct amdgpu_nbio {
--- a/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c
+++ b/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c
@@ -490,6 +490,18 @@ static void nbio_v2_3_apply_lc_spc_mode_
}
}

+static void nbio_v2_3_apply_l1_link_width_reconfig_wa(struct amdgpu_device *adev)
+{
+ uint32_t reg_data = 0;
+
+ if (adev->asic_type != CHIP_NAVI10)
+ return;
+
+ reg_data = RREG32_PCIE(smnPCIE_LC_LINK_WIDTH_CNTL);
+ reg_data |= PCIE_LC_LINK_WIDTH_CNTL__LC_L1_RECONFIG_EN_MASK;
+ WREG32_PCIE(smnPCIE_LC_LINK_WIDTH_CNTL, reg_data);
+}
+
const struct amdgpu_nbio_funcs nbio_v2_3_funcs = {
.get_hdp_flush_req_offset = nbio_v2_3_get_hdp_flush_req_offset,
.get_hdp_flush_done_offset = nbio_v2_3_get_hdp_flush_done_offset,
@@ -512,4 +524,5 @@ const struct amdgpu_nbio_funcs nbio_v2_3
.enable_aspm = nbio_v2_3_enable_aspm,
.program_aspm = nbio_v2_3_program_aspm,
.apply_lc_spc_mode_wa = nbio_v2_3_apply_lc_spc_mode_wa,
+ .apply_l1_link_width_reconfig_wa = nbio_v2_3_apply_l1_link_width_reconfig_wa,
};
--- a/drivers/gpu/drm/amd/amdgpu/nv.c
+++ b/drivers/gpu/drm/amd/amdgpu/nv.c
@@ -1076,6 +1076,9 @@ static int nv_common_hw_init(void *handl
if (adev->nbio.funcs->apply_lc_spc_mode_wa)
adev->nbio.funcs->apply_lc_spc_mode_wa(adev);

+ if (adev->nbio.funcs->apply_l1_link_width_reconfig_wa)
+ adev->nbio.funcs->apply_l1_link_width_reconfig_wa(adev);
+
/* enable pcie gen2/3 link */
nv_pcie_gen3_enable(adev);
/* enable aspm */