From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- drivers/hid/hid-axff.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) create mode 100644 drivers/hid/hid-axff.c (limited to 'drivers/hid/hid-axff.c') diff --git a/drivers/hid/hid-axff.c b/drivers/hid/hid-axff.c new file mode 100644 index 000000000..2f4644708 --- /dev/null +++ b/drivers/hid/hid-axff.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Force feedback support for ACRUX game controllers + * + * From what I have gathered, these devices are mass produced in China + * by several vendors. They often share the same design as the original + * Xbox 360 controller. + * + * 1a34:0802 "ACRUX USB GAMEPAD 8116" + * - tested with an EXEQ EQ-PCU-02090 game controller. + * + * Copyright (c) 2010 Sergei Kolzun + */ + +/* + */ + +#include +#include +#include +#include + +#include "hid-ids.h" + +#ifdef CONFIG_HID_ACRUX_FF + +struct axff_device { + struct hid_report *report; +}; + +static int axff_play(struct input_dev *dev, void *data, struct ff_effect *effect) +{ + struct hid_device *hid = input_get_drvdata(dev); + struct axff_device *axff = data; + struct hid_report *report = axff->report; + int field_count = 0; + int left, right; + int i, j; + + left = effect->u.rumble.strong_magnitude; + right = effect->u.rumble.weak_magnitude; + + dbg_hid("called with 0x%04x 0x%04x", left, right); + + left = left * 0xff / 0xffff; + right = right * 0xff / 0xffff; + + for (i = 0; i < report->maxfield; i++) { + for (j = 0; j < report->field[i]->report_count; j++) { + report->field[i]->value[j] = + field_count % 2 ? right : left; + field_count++; + } + } + + dbg_hid("running with 0x%02x 0x%02x", left, right); + hid_hw_request(hid, axff->report, HID_REQ_SET_REPORT); + + return 0; +} + +static int ax_input_configured(struct hid_device *hid, struct hid_input *hidinput) +{ + struct axff_device *axff; + struct hid_report *report; + struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; + struct input_dev *dev = hidinput->input; + int field_count = 0; + int i, j; + int error; + + if (!list_is_first(&hidinput->list, &hid->inputs)) + return 0; + + report = list_first_entry_or_null(report_list, struct hid_report, list); + if (!report) { + hid_err(hid, "no output reports found\n"); + return -ENODEV; + } + for (i = 0; i < report->maxfield; i++) { + for (j = 0; j < report->field[i]->report_count; j++) { + report->field[i]->value[j] = 0x00; + field_count++; + } + } + + if (field_count < 4 && hid->product != 0xf705) { + hid_err(hid, "not enough fields in the report: %d\n", + field_count); + return -ENODEV; + } + + axff = kzalloc_obj(struct axff_device); + if (!axff) + return -ENOMEM; + + axff->report = report; + set_bit(FF_RUMBLE, dev->ffbit); + + error = input_ff_create_memless(dev, axff, axff_play); + if (error) + goto err_free_mem; + + hid_hw_request(hid, axff->report, HID_REQ_SET_REPORT); + + hid_info(hid, "Force Feedback for ACRUX game controllers by Sergei Kolzun \n"); + + return 0; + +err_free_mem: + kfree(axff); + return error; +} +#else +static inline int ax_input_configured(struct hid_device *hid, + struct hid_input *hidinput) +{ + return 0; +} +#endif + +static int ax_probe(struct hid_device *hdev, const struct hid_device_id *id) +{ + int error; + + dev_dbg(&hdev->dev, "ACRUX HID hardware probe...\n"); + + error = hid_parse(hdev); + if (error) { + hid_err(hdev, "parse failed\n"); + return error; + } + + error = hid_hw_start(hdev, HID_CONNECT_DEFAULT); + if (error) { + hid_err(hdev, "hw start failed\n"); + return error; + } + /* + * We need to start polling device right away, otherwise + * it will go into a coma. + */ + error = hid_hw_open(hdev); + if (error) { + dev_err(&hdev->dev, "hw open failed\n"); + hid_hw_stop(hdev); + return error; + } + + return 0; +} + +static void ax_remove(struct hid_device *hdev) +{ + hid_hw_close(hdev); + hid_hw_stop(hdev); +} + +static const struct hid_device_id ax_devices[] = { + { HID_USB_DEVICE(USB_VENDOR_ID_ACRUX, 0x0802), }, + { HID_USB_DEVICE(USB_VENDOR_ID_ACRUX, 0xf705), }, + { } +}; +MODULE_DEVICE_TABLE(hid, ax_devices); + +static struct hid_driver ax_driver = { + .name = "acrux", + .id_table = ax_devices, + .probe = ax_probe, + .remove = ax_remove, + .input_configured = ax_input_configured, +}; +module_hid_driver(ax_driver); + +MODULE_AUTHOR("Sergei Kolzun"); +MODULE_DESCRIPTION("Force feedback support for ACRUX game controllers"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1