From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- drivers/hid/hid-emsff.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 drivers/hid/hid-emsff.c (limited to 'drivers/hid/hid-emsff.c') diff --git a/drivers/hid/hid-emsff.c b/drivers/hid/hid-emsff.c new file mode 100644 index 000000000..d8e559e05 --- /dev/null +++ b/drivers/hid/hid-emsff.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Force feedback support for EMS Trio Linker Plus II + * + * Copyright (c) 2010 Ignaz Forster + */ + +/* + */ + + +#include +#include +#include + +#include "hid-ids.h" + +struct emsff_device { + struct hid_report *report; +}; + +static int emsff_play(struct input_dev *dev, void *data, + struct ff_effect *effect) +{ + struct hid_device *hid = input_get_drvdata(dev); + struct emsff_device *emsff = data; + int weak, strong; + + weak = effect->u.rumble.weak_magnitude; + strong = effect->u.rumble.strong_magnitude; + + dbg_hid("called with 0x%04x 0x%04x\n", strong, weak); + + weak = weak * 0xff / 0xffff; + strong = strong * 0xff / 0xffff; + + emsff->report->field[0]->value[1] = weak; + emsff->report->field[0]->value[2] = strong; + + dbg_hid("running with 0x%02x 0x%02x\n", strong, weak); + hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); + + return 0; +} + +static int ems_input_configured(struct hid_device *hid, struct hid_input *hidinput) +{ + struct emsff_device *emsff; + struct hid_report *report; + struct list_head *report_list = + &hid->report_enum[HID_OUTPUT_REPORT].report_list; + struct input_dev *dev = hidinput->input; + 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; + } + if (report->maxfield < 1) { + hid_err(hid, "no fields in the report\n"); + return -ENODEV; + } + + if (report->field[0]->report_count < 7) { + hid_err(hid, "not enough values in the field\n"); + return -ENODEV; + } + + emsff = kzalloc_obj(struct emsff_device); + if (!emsff) + return -ENOMEM; + + emsff->report = report; + set_bit(FF_RUMBLE, dev->ffbit); + + error = input_ff_create_memless(dev, emsff, emsff_play); + if (error) { + kfree(emsff); + return error; + } + + emsff->report->field[0]->value[0] = 0x01; + emsff->report->field[0]->value[1] = 0x00; + emsff->report->field[0]->value[2] = 0x00; + emsff->report->field[0]->value[3] = 0x00; + emsff->report->field[0]->value[4] = 0x00; + emsff->report->field[0]->value[5] = 0x00; + emsff->report->field[0]->value[6] = 0x00; + hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); + + hid_info(hid, "force feedback for EMS based devices by Ignaz Forster \n"); + + return 0; +} + +static const struct hid_device_id ems_devices[] = { + { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) }, + { } +}; +MODULE_DEVICE_TABLE(hid, ems_devices); + +static struct hid_driver ems_driver = { + .name = "hkems", + .id_table = ems_devices, + .input_configured = ems_input_configured, +}; +module_hid_driver(ems_driver); + +MODULE_DESCRIPTION("Force feedback support for EMS Trio Linker Plus II"); +MODULE_LICENSE("GPL"); + -- cgit v1.3.1