Re: [PATCH v11 6/7] drm/xe/xe_sysctrl: Add System Controller power management support

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 19-03-2026 23:00, Anoop, Vijay wrote:
> From: Anoop Vijay <anoop.c.vijay@intel.com>
>
> Add suspend and resume handlers for System Controller to handle system
> (S3/S4) and runtime power management transitions.
>
> The handlers disable SoC remapper region before entering low power
> states and restore remapper configuration and mailbox interface on
> resume, re-establishing communication with firmware.
>
> Signed-off-by: Anoop Vijay <anoop.c.vijay@intel.com>
> Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> ---
> v10: (Riana, Umesh)
> - Added sysctrl suspend/resume handling
>
> v11: (Badal)
> - Remove explicit SoC remapper disable on suspend
> ---
>   drivers/gpu/drm/xe/xe_pm.c      | 11 +++++++++
>   drivers/gpu/drm/xe/xe_sysctrl.c | 44 +++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/xe/xe_sysctrl.h |  2 ++
>   3 files changed, 57 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index 01185f10a883..abdddd44a575 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -26,6 +26,7 @@
>   #include "xe_pcode.h"
>   #include "xe_pxp.h"
>   #include "xe_sriov_vf_ccs.h"
> +#include "xe_sysctrl.h"
>   #include "xe_trace.h"
>   #include "xe_vm.h"
>   #include "xe_wa.h"
> @@ -206,6 +207,8 @@ int xe_pm_suspend(struct xe_device *xe)
>   
>   	xe_i2c_pm_suspend(xe);
>   
> +	xe_sysctrl_pm_suspend(xe);
> +
>   	drm_dbg(&xe->drm, "Device suspended\n");
>   	xe_pm_block_end_signalling();
>   
> @@ -259,6 +262,8 @@ int xe_pm_resume(struct xe_device *xe)
>   
>   	xe_i2c_pm_resume(xe, true);
>   
> +	xe_sysctrl_pm_resume(xe);
> +
>   	xe_irq_resume(xe);
>   
>   	for_each_gt(gt, xe, id) {
> @@ -618,6 +623,9 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
>   
>   	xe_i2c_pm_suspend(xe);
>   
> +	if (xe->d3cold.allowed)
> +		xe_sysctrl_pm_suspend(xe);
> +
>   	xe_rpm_lockmap_release(xe);
>   	xe_pm_write_callback_task(xe, NULL);
>   	return 0;
> @@ -670,6 +678,9 @@ int xe_pm_runtime_resume(struct xe_device *xe)
>   
>   	xe_i2c_pm_resume(xe, xe->d3cold.allowed);
>   
> +	if (xe->d3cold.allowed)
> +		xe_sysctrl_pm_resume(xe);
> +
>   	xe_irq_resume(xe);
>   
>   	for_each_gt(gt, xe, id) {
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl.c b/drivers/gpu/drm/xe/xe_sysctrl.c
> index 84e3b70043a1..d8f1f8cc2244 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl.c
> +++ b/drivers/gpu/drm/xe/xe_sysctrl.c
> @@ -82,3 +82,47 @@ int xe_sysctrl_init(struct xe_device *xe)
>   
>   	return 0;
>   }
> +
> +/**
> + * xe_sysctrl_pm_suspend() - System Controller suspend handler
> + * @xe: xe device instance
> + *
> + * Invoked during system suspend (S3/S4) and runtime suspend to D3.
> + *
> + * The SoC remapper region is cleared automatically by hardware on D3
> + * cold entry. No action is required. This function is kept to preserve
> + * suspend/resume symmetry and provide a hook for future System Controller
> + * suspend handling.
> + */
> +void xe_sysctrl_pm_suspend(struct xe_device *xe)
> +{
> +	if (!xe->info.has_sysctrl)
> +		return;
> +
> +	if (IS_SRIOV_VF(xe))
> +		return;
> +
> +	/* SoC remapper region is disabled automatically on D3 cold entry; no action required. */

This is empty function and need to be removed.

Thanks,
Badal

> +}
> +
> +/**
> + * xe_sysctrl_pm_resume() - System Controller resume handler
> + * @xe: xe device instance
> + *
> + * Invoked during system resume (S3/S4 to S0) and runtime resume from D3cold.
> + * Restores SoC remapper configuration and reinitializes mailbox interface.
> + */
> +void xe_sysctrl_pm_resume(struct xe_device *xe)
> +{
> +	struct xe_sysctrl *sc = &xe->sc;
> +
> +	if (!xe->info.has_sysctrl)
> +		return;
> +
> +	if (IS_SRIOV_VF(xe))
> +		return;
> +
> +	xe->soc_remapper.set_sysctrl_region(xe, SYSCTRL_MAILBOX_INDEX);
> +
> +	xe_sysctrl_mailbox_init(sc);
> +}
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl.h b/drivers/gpu/drm/xe/xe_sysctrl.h
> index d5d8735038ae..a816feed8da6 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl.h
> +++ b/drivers/gpu/drm/xe/xe_sysctrl.h
> @@ -17,5 +17,7 @@ static inline struct xe_device *sc_to_xe(struct xe_sysctrl *sc)
>   }
>   
>   int xe_sysctrl_init(struct xe_device *xe);
> +void xe_sysctrl_pm_suspend(struct xe_device *xe);
> +void xe_sysctrl_pm_resume(struct xe_device *xe);
>   
>   #endif