HID: intel-ish-hid: Use dedicated unbound workqueues to prevent resume blocking

During suspend/resume tests with S2IDLE, some ISH functional failures were
observed because of delay in executing ISH resume handler. Here
schedule_work() is used from resume handler to do actual work.
schedule_work() uses system_wq, which is a per CPU work queue. Although
the queuing is not bound to a CPU, but it prefers local CPU of the caller,
unless prohibited.

Users of this work queue are not supposed to queue long running work.
But in practice, there are scenarios where long running work items are
queued on other unbound workqueues, occupying the CPU. As a result, the
ISH resume handler may not get a chance to execute in a timely manner.

In one scenario, one of the ish_resume_handler() executions was delayed
nearly 1 second because another work item on an unbound workqueue occupied
the same CPU. This delay causes ISH functionality failures.

A similar issue was previously observed where the ISH HID driver timed out
while getting the HID descriptor during S4 resume in the recovery kernel,
likely caused by the same workqueue contention problem.

Create dedicated unbound workqueues for all ISH operations to allow work
items to execute on any available CPU, eliminating CPU-specific bottlenecks
and improving resume reliability under varying system loads. Also ISH has
three different components, a bus driver which implements ISH protocols, a
PCI interface layer and HID interface. Use one dedicated work queue for all
of them.

Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/intel-ish-hid/ipc/ipc.c b/drivers/hid/intel-ish-hid/ipc/ipc.c
index 3ddaa2cd39d555f08a546c4ba42dd2d02cf8bdb1..9958f2968c4ffdb4f1f77d7f9869dff3b52d356d 100644 (file)
--- a/drivers/hid/intel-ish-hid/ipc/ipc.c
+++ b/drivers/hid/intel-ish-hid/ipc/ipc.c
@@ -628,7 +628,7 @@ static void recv_ipc(struct ishtp_device *dev, uint32_t doorbell_val)
                if (!ishtp_dev) {
                        ishtp_dev = dev;
                }
-               schedule_work(&fw_reset_work);
+               queue_work(dev->unbound_wq, &fw_reset_work);
                break;
 
        case MNG_RESET_NOTIFY_ACK:
@@ -933,6 +933,21 @@ static const struct ishtp_hw_ops ish_hw_ops = {
        .dma_no_cache_snooping = _dma_no_cache_snooping
 };
 
+static struct workqueue_struct *devm_ishtp_alloc_workqueue(struct device *dev)
+{
+       struct workqueue_struct *wq;
+
+       wq = alloc_workqueue("ishtp_unbound_%d", WQ_UNBOUND, 0, dev->id);
+       if (!wq)
+               return NULL;
+
+       if (devm_add_action_or_reset(dev, (void (*)(void *))destroy_workqueue,
+                                    wq))
+               return NULL;
+
+       return wq;
+}
+
 /**
  * ish_dev_init() -Initialize ISH devoce
  * @pdev: PCI device
@@ -953,6 +968,10 @@ struct ishtp_device *ish_dev_init(struct pci_dev *pdev)
        if (!dev)
                return NULL;
 
+       dev->unbound_wq = devm_ishtp_alloc_workqueue(&pdev->dev);
+       if (!dev->unbound_wq)
+               return NULL;
+
        dev->devc = &pdev->dev;
        ishtp_device_init(dev);
 

diff --git a/drivers/hid/intel-ish-hid/ipc/pci-ish.c b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
index 9d150ce234f25331081a6493d2fb41672b23c738..b748ac6fbfdc73c0c0b1ac224b66c6ffa6076e46 100644 (file)
--- a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
+++ b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
@@ -384,7 +384,7 @@ static int __maybe_unused ish_resume(struct device *device)
        ish_resume_device = device;
        dev->resume_flag = 1;
 
-       schedule_work(&resume_work);
+       queue_work(dev->unbound_wq, &resume_work);
 
        return 0;
 }

diff --git a/drivers/hid/intel-ish-hid/ishtp-hid-client.c b/drivers/hid/intel-ish-hid/ishtp-hid-client.c
index d8c3c54a8c0f2a757717c08400fc24516f0296f6..f61add862b6b3fb60678b85d016f3b5c35ced6f6 100644 (file)
--- a/drivers/hid/intel-ish-hid/ishtp-hid-client.c
+++ b/drivers/hid/intel-ish-hid/ishtp-hid-client.c
@@ -860,7 +860,7 @@ static int hid_ishtp_cl_reset(struct ishtp_cl_device *cl_device)
        hid_ishtp_trace(client_data, "%s hid_ishtp_cl %p\n", __func__,
                        hid_ishtp_cl);
 
-       schedule_work(&client_data->work);
+       queue_work(ishtp_get_workqueue(cl_device), &client_data->work);
 
        return 0;
 }
@@ -902,7 +902,7 @@ static int hid_ishtp_cl_resume(struct device *device)
 
        hid_ishtp_trace(client_data, "%s hid_ishtp_cl %p\n", __func__,
                        hid_ishtp_cl);
-       schedule_work(&client_data->resume_work);
+       queue_work(ishtp_get_workqueue(cl_device), &client_data->resume_work);
        return 0;
 }
 

diff --git a/drivers/hid/intel-ish-hid/ishtp/bus.c b/drivers/hid/intel-ish-hid/ishtp/bus.c
index 93a0432e7058143df6fafd2981639878d5891a24..c6ce37244e49758ed271d976bba3af13fbb0aadd 100644 (file)
--- a/drivers/hid/intel-ish-hid/ishtp/bus.c
+++ b/drivers/hid/intel-ish-hid/ishtp/bus.c
@@ -541,7 +541,7 @@ void ishtp_cl_bus_rx_event(struct ishtp_cl_device *device)
                return;
 
        if (device->event_cb)
-               schedule_work(&device->event_work);
+               queue_work(device->ishtp_dev->unbound_wq, &device->event_work);
 }
 
 /**
@@ -876,6 +876,22 @@ struct device *ishtp_get_pci_device(struct ishtp_cl_device *device)
 }
 EXPORT_SYMBOL(ishtp_get_pci_device);
 
+/**
+ * ishtp_get_workqueue - Retrieve the workqueue associated with an ISHTP device
+ * @cl_device: Pointer to the ISHTP client device structure
+ *
+ * Returns the workqueue_struct pointer (unbound_wq) associated with the given
+ * ISHTP client device. This workqueue is typically used for scheduling work
+ * related to the device.
+ *
+ * Return: Pointer to struct workqueue_struct.
+ */
+struct workqueue_struct *ishtp_get_workqueue(struct ishtp_cl_device *cl_device)
+{
+       return cl_device->ishtp_dev->unbound_wq;
+}
+EXPORT_SYMBOL(ishtp_get_workqueue);
+
 /**
  * ishtp_trace_callback() - Return trace callback
  * @cl_device: ISH-TP client device instance

diff --git a/drivers/hid/intel-ish-hid/ishtp/hbm.c b/drivers/hid/intel-ish-hid/ishtp/hbm.c
index 8ee5467127d87294631350ee49350cd718f86e96..97c4fcd9e3c6f2c3ccf696accd7e6196617f637f 100644 (file)
--- a/drivers/hid/intel-ish-hid/ishtp/hbm.c
+++ b/drivers/hid/intel-ish-hid/ishtp/hbm.c
@@ -573,7 +573,7 @@ void ishtp_hbm_dispatch(struct ishtp_device *dev,
 
                /* Start firmware loading process if it has loader capability */
                if (version_res->host_version_supported & ISHTP_SUPPORT_CAP_LOADER)
-                       schedule_work(&dev->work_fw_loader);
+                       queue_work(dev->unbound_wq, &dev->work_fw_loader);
 
                dev->version.major_version = HBM_MAJOR_VERSION;
                dev->version.minor_version = HBM_MINOR_VERSION;
@@ -864,7 +864,7 @@ void        recv_hbm(struct ishtp_device *dev, struct ishtp_msg_hdr *ishtp_hdr)
        dev->rd_msg_fifo_tail = (dev->rd_msg_fifo_tail + IPC_PAYLOAD_SIZE) %
                (RD_INT_FIFO_SIZE * IPC_PAYLOAD_SIZE);
        spin_unlock_irqrestore(&dev->rd_msg_spinlock, flags);
-       schedule_work(&dev->bh_hbm_work);
+       queue_work(dev->unbound_wq, &dev->bh_hbm_work);
 eoi:
        return;
 }

diff --git a/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h b/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h
index 23db97ecf21cd903550c3cbd71f4b16183da0abb..4b0596eadf1ccee66fdc8829ff438d88ee49b61d 100644 (file)
--- a/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h
+++ b/drivers/hid/intel-ish-hid/ishtp/ishtp-dev.h
@@ -175,6 +175,9 @@ struct ishtp_device {
        struct hbm_version version;
        int transfer_path; /* Choice of transfer path: IPC or DMA */
 
+       /* Alloc a dedicated unbound workqueue for ishtp device */
+       struct workqueue_struct *unbound_wq;
+
        /* work structure for scheduling firmware loading tasks */
        struct work_struct work_fw_loader;
        /* waitq for waiting for command response from the firmware loader */

diff --git a/include/linux/intel-ish-client-if.h b/include/linux/intel-ish-client-if.h
index dfbf7d9d7bb5a876eb366b682114bc67a0797b70..b235fd84f4780469590df9d8f69f2aa42c350e90 100644 (file)
--- a/include/linux/intel-ish-client-if.h
+++ b/include/linux/intel-ish-client-if.h
@@ -87,6 +87,8 @@ bool ishtp_wait_resume(struct ishtp_device *dev);
 ishtp_print_log ishtp_trace_callback(struct ishtp_cl_device *cl_device);
 /* Get device pointer of PCI device for DMA acces */
 struct device *ishtp_get_pci_device(struct ishtp_cl_device *cl_device);
+/* Get the ISHTP workqueue */
+struct workqueue_struct *ishtp_get_workqueue(struct ishtp_cl_device *cl_device);
 
 struct ishtp_cl *ishtp_cl_allocate(struct ishtp_cl_device *cl_device);
 void ishtp_cl_free(struct ishtp_cl *cl);