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-picolcd_backlight.c | 103 ++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 drivers/hid/hid-picolcd_backlight.c (limited to 'drivers/hid/hid-picolcd_backlight.c') diff --git a/drivers/hid/hid-picolcd_backlight.c b/drivers/hid/hid-picolcd_backlight.c new file mode 100644 index 000000000..4b43b6453 --- /dev/null +++ b/drivers/hid/hid-picolcd_backlight.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-only +/*************************************************************************** + * Copyright (C) 2010-2012 by Bruno Prémont * + * * + * Based on Logitech G13 driver (v0.4) * + * Copyright (C) 2009 by Rick L. Vinyard, Jr. * + * * + ***************************************************************************/ + +#include + +#include + +#include "hid-picolcd.h" + +static int picolcd_get_brightness(struct backlight_device *bdev) +{ + struct picolcd_data *data = bl_get_data(bdev); + return data->lcd_brightness; +} + +static int picolcd_set_brightness(struct backlight_device *bdev) +{ + struct picolcd_data *data = bl_get_data(bdev); + struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev); + unsigned long flags; + + if (!report || report->maxfield != 1 || report->field[0]->report_count != 1) + return -ENODEV; + + data->lcd_brightness = bdev->props.brightness & 0x0ff; + data->lcd_power = bdev->props.power; + spin_lock_irqsave(&data->lock, flags); + hid_set_field(report->field[0], 0, + data->lcd_power == BACKLIGHT_POWER_ON ? data->lcd_brightness : 0); + if (!(data->status & PICOLCD_FAILED)) + hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT); + spin_unlock_irqrestore(&data->lock, flags); + return 0; +} + +static const struct backlight_ops picolcd_blops = { + .update_status = picolcd_set_brightness, + .get_brightness = picolcd_get_brightness, +}; + +int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report) +{ + struct device *dev = &data->hdev->dev; + struct backlight_device *bdev; + struct backlight_properties props; + if (!report) + return -ENODEV; + if (report->maxfield != 1 || report->field[0]->report_count != 1 || + report->field[0]->report_size != 8) { + dev_err(dev, "unsupported BRIGHTNESS report"); + return -EINVAL; + } + + memset(&props, 0, sizeof(props)); + props.type = BACKLIGHT_RAW; + props.max_brightness = 0xff; + bdev = backlight_device_register(dev_name(dev), dev, data, + &picolcd_blops, &props); + if (IS_ERR(bdev)) { + dev_err(dev, "failed to register backlight\n"); + return PTR_ERR(bdev); + } + bdev->props.brightness = 0xff; + data->lcd_brightness = 0xff; + data->backlight = bdev; + picolcd_set_brightness(bdev); + return 0; +} + +void picolcd_exit_backlight(struct picolcd_data *data) +{ + struct backlight_device *bdev = data->backlight; + + data->backlight = NULL; + backlight_device_unregister(bdev); +} + +int picolcd_resume_backlight(struct picolcd_data *data) +{ + if (!data->backlight) + return 0; + return picolcd_set_brightness(data->backlight); +} + +#ifdef CONFIG_PM +void picolcd_suspend_backlight(struct picolcd_data *data) +{ + int bl_power = data->lcd_power; + if (!data->backlight) + return; + + data->backlight->props.power = BACKLIGHT_POWER_OFF; + picolcd_set_brightness(data->backlight); + data->lcd_power = data->backlight->props.power = bl_power; +} +#endif /* CONFIG_PM */ + -- cgit v1.3.1