From e22d7acf9f47b01c9a538f3dac5c8e8d46fbca96 Mon Sep 17 00:00:00 2001 From: Aradhya Bhatia Date: Fri, 16 May 2025 14:19:02 +0000 Subject: [PATCH 1/2] drm/xe/guc: Make creation of SLPC debugfs files conditional MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Platforms that do not support SLPC are exempted from the GuC PC support. The GuC PC does not get initialized, and neither do its BOs get created. This causes a problem because the GuC PC debugfs file is still being created. Whenever the file is attempted to read, it causes a NULL pointer dereference on the supposed BO of the GuC PC. So, make the creation of SLPC debugfs files conditional to when SLPC features are supported. Fixes: aaab5404b16f ("drm/xe: Introduce GuC PC debugfs") Suggested-by: Matt Roper Reviewed-by: Tejas Upadhyay Reviewed-by: Stuart Summers Signed-off-by: Aradhya Bhatia Link: https://lore.kernel.org/r/20250516141902.5614-1-aradhya.bhatia@intel.com Signed-off-by: Matt Roper (cherry picked from commit 17486cf3df5320752cc67ee8bcb2379d1b9de76c) Signed-off-by: Thomas Hellström --- drivers/gpu/drm/xe/xe_guc_debugfs.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_guc_debugfs.c b/drivers/gpu/drm/xe/xe_guc_debugfs.c index f33013f8a0f3..0b102ab46c4d 100644 --- a/drivers/gpu/drm/xe/xe_guc_debugfs.c +++ b/drivers/gpu/drm/xe/xe_guc_debugfs.c @@ -113,23 +113,34 @@ static const struct drm_info_list vf_safe_debugfs_list[] = { { "guc_ctb", .show = guc_debugfs_show, .data = guc_ctb }, }; +/* For GuC debugfs files that require the SLPC support */ +static const struct drm_info_list slpc_debugfs_list[] = { + { "guc_pc", .show = guc_debugfs_show, .data = guc_pc }, +}; + /* everything else should be added here */ static const struct drm_info_list pf_only_debugfs_list[] = { { "guc_log", .show = guc_debugfs_show, .data = guc_log }, { "guc_log_dmesg", .show = guc_debugfs_show, .data = guc_log_dmesg }, - { "guc_pc", .show = guc_debugfs_show, .data = guc_pc }, }; void xe_guc_debugfs_register(struct xe_guc *guc, struct dentry *parent) { - struct drm_minor *minor = guc_to_xe(guc)->drm.primary; + struct xe_device *xe = guc_to_xe(guc); + struct drm_minor *minor = xe->drm.primary; drm_debugfs_create_files(vf_safe_debugfs_list, ARRAY_SIZE(vf_safe_debugfs_list), parent, minor); - if (!IS_SRIOV_VF(guc_to_xe(guc))) + if (!IS_SRIOV_VF(xe)) { drm_debugfs_create_files(pf_only_debugfs_list, ARRAY_SIZE(pf_only_debugfs_list), parent, minor); + + if (!xe->info.skip_guc_pc) + drm_debugfs_create_files(slpc_debugfs_list, + ARRAY_SIZE(slpc_debugfs_list), + parent, minor); + } } From 879ede53958f7bab79a88888f77e0ca91f0f77da Mon Sep 17 00:00:00 2001 From: Aradhya Bhatia Date: Fri, 16 May 2025 12:43:55 +0000 Subject: [PATCH 2/2] drm/xe: Default auto_link_downgrade status to false MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit xe_pcode_read() can return back successfully without updating the variable 'val'. This can cause an arbitrary value to show up in the sysfs file. Allow the auto_link_downgrade_status to default to 0 to avoid any arbitrary value from coming up. Fixes: 0e414bf7ad01 ("drm/xe: Expose PCIe link downgrade attributes") Reviewed-by: Tejas Upadhyay Signed-off-by: Aradhya Bhatia Link: https://lore.kernel.org/r/20250516124355.4872-1-aradhya.bhatia@intel.com Signed-off-by: Matt Roper (cherry picked from commit a7f87deac2295d11865048bcb9c2de369b52ed93) Signed-off-by: Thomas Hellström --- drivers/gpu/drm/xe/xe_device_sysfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xe/xe_device_sysfs.c b/drivers/gpu/drm/xe/xe_device_sysfs.c index 9628e9a0a0af..2e657692e5b5 100644 --- a/drivers/gpu/drm/xe/xe_device_sysfs.c +++ b/drivers/gpu/drm/xe/xe_device_sysfs.c @@ -124,7 +124,8 @@ auto_link_downgrade_status_show(struct device *dev, struct device_attribute *att { struct pci_dev *pdev = to_pci_dev(dev); struct xe_device *xe = pdev_to_xe_device(pdev); - u32 val; + /* default the auto_link_downgrade status to 0 */ + u32 val = 0; int ret; xe_pm_runtime_get(xe);