Re: [PATCH v5 2/3] drm/xe/sysctrl: Add system controller event support

Tauro, Riana
2026-04-09T09:58:18Z

On 4/7/2026 4:36 PM, Raag Jadav wrote:
> System controller reports different types of events to GFX endpoint for
> different usecases, add initial support for them. This will be further
> extended to service those usecases.
>
> Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> Reviewed-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
> ---
> v2: Handle unexpected response length (Mallesh)
> v3: Handle event flood (Mallesh)
> ---
> drivers/gpu/drm/xe/Makefile | 1 +
> drivers/gpu/drm/xe/xe_sysctrl.c | 7 ++
> drivers/gpu/drm/xe/xe_sysctrl.h | 1 +
> drivers/gpu/drm/xe/xe_sysctrl_event.c | 88 +++++++++++++++++++++
> drivers/gpu/drm/xe/xe_sysctrl_event_types.h | 52 ++++++++++++
> drivers/gpu/drm/xe/xe_sysctrl_mailbox.h | 10 +++
> 6 files changed, 159 insertions(+)
> create mode 100644 drivers/gpu/drm/xe/xe_sysctrl_event.c
> create mode 100644 drivers/gpu/drm/xe/xe_sysctrl_event_types.h
>
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index ab1e0b3b332d..c0e820eeea30 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -125,6 +125,7 @@ xe-y += xe_bb.o \
> xe_survivability_mode.o \
> xe_sync.o \
> xe_sysctrl.o \
> + xe_sysctrl_event.o \
> xe_sysctrl_mailbox.o \
> xe_tile.o \
> xe_tile_sysfs.o \
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl.c b/drivers/gpu/drm/xe/xe_sysctrl.c
> index afa9654668a2..7003b1da6e46 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl.c
> +++ b/drivers/gpu/drm/xe/xe_sysctrl.c
> @@ -12,6 +12,7 @@
> #include "regs/xe_sysctrl_regs.h"
> #include "xe_device.h"
> #include "xe_mmio.h"
> +#include "xe_pm.h"
> #include "xe_soc_remapper.h"
> #include "xe_sysctrl.h"
> #include "xe_sysctrl_mailbox.h"
> @@ -39,6 +40,12 @@ static void sysctrl_fini(void *arg)
>
> static void xe_sysctrl_work(struct work_struct *work)
> {
> + struct xe_sysctrl *sc = container_of(work, struct xe_sysctrl, work);
> + struct xe_device *xe = sc_to_xe(sc);
> +
> + guard(xe_pm_runtime)(xe);
> + guard(mutex)(&sc->work_lock);
> + xe_sysctrl_event(sc);
> }
>
> /**
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl.h b/drivers/gpu/drm/xe/xe_sysctrl.h
> index f7469bfc9324..090dffb6d55f 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl.h
> +++ b/drivers/gpu/drm/xe/xe_sysctrl.h
> @@ -16,6 +16,7 @@ static inline struct xe_device *sc_to_xe(struct xe_sysctrl *sc)
> return container_of(sc, struct xe_device, sc);
> }
>
> +void xe_sysctrl_event(struct xe_sysctrl *sc);
> int xe_sysctrl_init(struct xe_device *xe);
> void xe_sysctrl_irq_handler(struct xe_device *xe, u32 master_ctl);
> void xe_sysctrl_pm_resume(struct xe_device *xe);
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl_event.c b/drivers/gpu/drm/xe/xe_sysctrl_event.c
> new file mode 100644
> index 000000000000..8a2e44f4f5e0
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sysctrl_event.c
> @@ -0,0 +1,88 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2026 Intel Corporation
> + */
> +
> +#include "xe_device.h"
> +#include "xe_irq.h"
> +#include "xe_printk.h"
> +#include "xe_sysctrl.h"
> +#include "xe_sysctrl_event_types.h"
> +#include "xe_sysctrl_mailbox.h"
> +#include "xe_sysctrl_mailbox_types.h"
> +
> +static void xe_sysctrl_get_pending_event(struct xe_sysctrl *sc,
> + struct xe_sysctrl_mailbox_command *command)
static functions don't need a xe prefix
> +{
> + struct xe_sysctrl_event_response response;
> + struct xe_device *xe = sc_to_xe(sc);
> + u32 count = 0;
> + size_t len;
> + int ret;
> +
> + command->data_out = &response;
> + command->data_out_len = sizeof(response);
Can be part of prepare command
> +
> + do {
> + memset(&response, 0, sizeof(response));
> +
> + ret = xe_sysctrl_send_command(sc, command, &len);
> + if (ret) {
> + xe_err(xe, "sysctrl: failed to get pending event %d\n", ret);
> + return;
> + }
> +
> + if (len != sizeof(response)) {
> + xe_err(xe, "sysctrl: unexpected pending event response length %zu\n", len);
> + return;
> + }
> +
> + if (response.event == XE_SYSCTRL_EVENT_THRESHOLD_CROSSED) {
> + xe_warn(xe, "[RAS]: counter threshold crossed\n");
> + } else {
> + xe_err(xe, "sysctrl: unexpected event %#x\n", response.event);
> + return;

Should we return here  if the event is not threshold_crossed.
The events left might still be valid.
If more event types are added, this might be an issue. Can't we just log
the unknown event and go ahead?

> + }
> +
> + if (++count > XE_SYSCTRL_EVENT_FLOOD) {
Can't the first response count be used as a reference for comparison?
Looks like the response count keeps decrementing for each command sent.

Also add a comment for the response.count behavior in the structure

> + xe_err(xe, "sysctrl: event flooding\n");
> + return;
> + }
> +
> + xe_dbg(xe, "sysctrl: %u events pending\n", response.count);
> + } while (response.count);
> +}
> +
> +static void xe_sysctrl_event_request_prep(struct xe_device *xe,
> + struct xe_sysctrl_app_msg_hdr *header,
> + struct xe_sysctrl_event_request *request)
static functions don't need a xe_ prefix
> +{
> + struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> +
> + header->data = REG_FIELD_PREP(APP_HDR_GROUP_ID_MASK, XE_SYSCTRL_GROUP_GFSP) |
> + REG_FIELD_PREP(APP_HDR_COMMAND_MASK, XE_SYSCTRL_CMD_GET_PENDING_EVENT);
> +
> + request->vector = xe_device_has_msix(xe) ? XE_IRQ_DEFAULT_MSIX : 0;
> + request->fn = PCI_FUNC(pdev->devfn);
> +}
> +
> +/**
> + * xe_sysctrl_event() - Handler for System Controller events
> + * @sc: System Controller instance
> + *
> + * Handle events generated by System Controller.
> + */
> +void xe_sysctrl_event(struct xe_sysctrl *sc)
> +{
> + struct xe_sysctrl_mailbox_command command = {};
> + struct xe_sysctrl_event_request request = {};
> + struct xe_sysctrl_app_msg_hdr header = {};
> +
> + xe_sysctrl_event_request_prep(sc_to_xe(sc), &header, &request);
> +
> + command.header = header;
> + command.data_in = &request;
> + command.data_in_len = sizeof(request);
> +
> + xe_sysctrl_get_pending_event(sc, &command);
> +}
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl_event_types.h b/drivers/gpu/drm/xe/xe_sysctrl_event_types.h
> new file mode 100644
> index 000000000000..9a26ad758a0b
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sysctrl_event_types.h
> @@ -0,0 +1,52 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2026 Intel Corporation
> + */
> +
> +#ifndef _XE_SYSCTRL_EVENT_TYPES_H_
> +#define _XE_SYSCTRL_EVENT_TYPES_H_
> +
> +#include <linux/types.h>
> +
> +#define XE_SYSCTRL_EVENT_DATA_LEN 59
> +
> +/* Modify as needed */
> +#define XE_SYSCTRL_EVENT_FLOOD 16
> +
> +enum xe_sysctrl_event {
> + XE_SYSCTRL_EVENT_THRESHOLD_CROSSED = 1,

Nit: 0x01

Add a one line comment

> +};
> +
> +/**
> + * struct xe_sysctrl_event_request - Request structure for pending event
> + */
> +struct xe_sysctrl_event_request {
> + /** @vector: MSI-X vector that was triggered */
> + u32 vector;
> + /** @fn: Function index (0-7) of PCIe device */
> + u32 fn:8;
> + /** @reserved: Reserved for future use */
> + u32 reserved:24;
> + /** @reserved2: Reserved for future use */
> + u32 reserved2[2];
> +} __packed;
> +
> +/**
> + * struct xe_sysctrl_event_response - Response structure for pending event
> + */
> +struct xe_sysctrl_event_response {
> + /** @count: Number of pending events */
> + u32 count;
> + /** @event: Pending event */
> + enum xe_sysctrl_event event;
> + /** @timestamp: Timestamp of most recent event */
> + u64 timestamp;
> + /** @extended: Event has extended payload */
> + u32 extended:1;
> + /** @reserved: Reserved for future use */
> + u32 reserved:31;
> + /** @data: Generic event data */
> + u32 data[XE_SYSCTRL_EVENT_DATA_LEN];
> +} __packed;
> +
> +#endif /* _XE_SYSCTRL_EVENT_TYPES_H_ */
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h
> index 91460be9e22c..d59a825597d3 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h
> +++ b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h
> @@ -23,6 +23,16 @@ struct xe_sysctrl_mailbox_command;
> #define XE_SYSCTRL_APP_HDR_VERSION(hdr) \
> FIELD_GET(APP_HDR_VERSION_MASK, le32_to_cpu((hdr)->data))
>
> +/* Command groups */
> +enum xe_sysctrl_group {
> + XE_SYSCTRL_GROUP_GFSP = 0x01,
> +};
> +
> +/* Commands supported by GFSP group */
> +enum xe_sysctrl_gfsp_cmd {
> + XE_SYSCTRL_CMD_GET_PENDING_EVENT = 0x07,
> +};
Move the enums to types.h along with structures.
Also had a one-line documentation for each

Thanks
Riana
> +
> void xe_sysctrl_mailbox_init(struct xe_sysctrl *sc);
> int xe_sysctrl_send_command(struct xe_sysctrl *sc,
> struct xe_sysctrl_mailbox_command *cmd,