Within the i915 driver, intel_pxp_fini is called through different paths.
i915_pci_shutdown → i915_driver_shutdown → intel_pxp_fini (new added)
i915_pci_remove → i915_driver_remove → i915_driver_unregister → intel_pxp_fini
For MEI-based PXP, which is mentioned in the commit message.
> Since disabling PCIe memory space affects all MMIO operations, PXP
> shutdown needs to be completed before this point. Calls
> intel_pxp_fini() before disabling memory space to ensure PXP cleanup can
> still access MMIO registers.
>From i915
Kernel_kexec
-> kernel_restart_prepare
-> pci_device_shutdown
-> i915_driver_shutdown
-> intel_pxp_fini
-> intel_pxp_tee_component_fini
// will delete component
>From mei
Kernel_kexec
-> kernel_restart_prepare
-> pci_device_shutdown
-> mei_me_shutdown
-> mei_stop
-> mei_cl_bus_remove_device
-> device_release_driver
->
device_release_driver_internal
->
mei_cl_device_remove
->
mei_pxp_remove
-> component_master_del
->take_down_aggregate_device
-> mei_component_master_unbind
->component_unbind_all
->component_unbind // will
not be called
->i915_pxp_tee_component_unbind
-> intel_pxp_fini_hw
After intel_pxp_tee_component_fini is called, for mei_me_shutdown stack,
component_unbind will not be called for component has been deleted.
-----Original Message-----
From: Jani Nikula <[email protected]>
Sent: Tuesday, January 20, 2026 1:51 AM
To: Yao, Jia <[email protected]>; [email protected]
Cc: Yao, Jia <[email protected]>; Zuo, Alex <[email protected]>; Lin,
Shuicheng <[email protected]>; Askar Safin <[email protected]>;
Pingfan Liu <[email protected]>; Chris Wilson <[email protected]>
Subject: Re: [PATCH v3] drm/i915: Clearing the Memory Space Enable bit when
disabling i915
On Tue, 20 Jan 2026, Jia Yao <[email protected]> wrote:
> In a kexec reboot scenario, the GPU's Global Graphics Translation
> Table
> (GGTT) retains its previous state after the kernel is reloaded, until
> i915 reinitializes the GGTT.
>
> The simple-framebuffer driver is initialized before i915 and accesses
> the PCIe memory space (GPU aperture) through outdated GGTT entries.
> This leads to invalid physical memory accesses, causing GPF or data
> corruption.
>
> To prevent such issues, the Memory Space Enable (MSE) bit in the PCI
> Command Register is cleared during i915_driver_shutdown. This disables
> all PCIe memory space access (including MMIO and aperture) at the hardware
> level.
> After the kernel is reloaded, access to the PCIe memory space will be
> forbidden until i915 is re-initialized.
>
> Since disabling PCIe memory space affects all MMIO operations, PXP
> shutdown needs to be completed before this point. Calls
> intel_pxp_fini() before disabling memory space to ensure PXP cleanup can
> still access MMIO registers.
>
> v2:
> - follow brace style
>
> v3:
> - revise description
>
> Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14598
> Cc: Alex Zuo <[email protected]>
> Cc: Shuicheng Lin <[email protected]>
> Cc: Askar Safin <[email protected]>
> Cc: Pingfan Liu <[email protected]>
> Suggested-by: Chris Wilson <[email protected]>
> Signed-off-by: Jia Yao <[email protected]>
> ---
> drivers/gpu/drm/i915/i915_driver.c | 35
> +++++++++++++++++++++++++++---
> 1 file changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_driver.c
> b/drivers/gpu/drm/i915/i915_driver.c
> index b46cb54ef5dc..766f85726b67 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -118,6 +118,33 @@
>
> static const struct drm_driver i915_drm_driver;
>
> +static int i915_enable_device(struct pci_dev *pdev) {
> + u32 cmd;
> + int ret;
> +
> + ret = pci_enable_device(pdev);
> + if (ret)
> + return ret;
> +
> + pci_read_config_dword(pdev, PCI_COMMAND, &cmd);
> + if (!(cmd & PCI_COMMAND_MEMORY))
> + pci_write_config_dword(pdev, PCI_COMMAND, cmd |
> +PCI_COMMAND_MEMORY);
> +
> + return 0;
> +}
> +
> +static void i915_disable_device(struct pci_dev *pdev) {
> + u32 cmd;
> +
> + pci_read_config_dword(pdev, PCI_COMMAND, &cmd);
> + if (cmd & PCI_COMMAND_MEMORY)
> + pci_write_config_dword(pdev, PCI_COMMAND, cmd &
> +~PCI_COMMAND_MEMORY);
> +
> + pci_disable_device(pdev);
> +}
> +
> static int i915_workqueues_init(struct drm_i915_private *dev_priv) {
> /*
> @@ -788,7 +815,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct
> pci_device_id *ent)
> struct intel_display *display;
> int ret;
>
> - ret = pci_enable_device(pdev);
> + ret = i915_enable_device(pdev);
> if (ret) {
> pr_err("Failed to enable graphics device: %pe\n", ERR_PTR(ret));
> return ret;
> @@ -796,7 +823,7 @@ int i915_driver_probe(struct pci_dev *pdev, const
> struct pci_device_id *ent)
>
> i915 = i915_driver_create(pdev, ent);
> if (IS_ERR(i915)) {
> - pci_disable_device(pdev);
> + i915_disable_device(pdev);
> return PTR_ERR(i915);
> }
>
> @@ -885,7 +912,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct
> pci_device_id *ent)
> enable_rpm_wakeref_asserts(&i915->runtime_pm);
> i915_driver_late_release(i915);
> out_pci_disable:
> - pci_disable_device(pdev);
> + i915_disable_device(pdev);
> i915_probe_error(i915, "Device initialization failed (%d)\n", ret);
> return ret;
> }
> @@ -1003,6 +1030,7 @@ void i915_driver_shutdown(struct
> drm_i915_private *i915)
>
> intel_dmc_suspend(display);
>
> + intel_pxp_fini(i915);
This is now called twice. Please fix it.
> i915_gem_suspend(i915);
>
> /*
> @@ -1020,6 +1048,7 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
> enable_rpm_wakeref_asserts(&i915->runtime_pm);
>
> intel_runtime_pm_driver_last_release(&i915->runtime_pm);
> + i915_disable_device(to_pci_dev(i915->drm.dev));
> }
>
> static bool suspend_to_idle(struct drm_i915_private *dev_priv)
--
Jani Nikula, Intel
