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/input/touchscreen.c | 208 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 drivers/input/touchscreen.c (limited to 'drivers/input/touchscreen.c') diff --git a/drivers/input/touchscreen.c b/drivers/input/touchscreen.c new file mode 100644 index 000000000..d699b24bb --- /dev/null +++ b/drivers/input/touchscreen.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Generic helper functions for touchscreens and other two-dimensional + * pointing devices + * + * Copyright (c) 2014 Sebastian Reichel + */ + +#include +#include +#include +#include +#include +#include + +static bool touchscreen_get_prop_u32(struct device *dev, + const char *property, + unsigned int default_value, + unsigned int *value) +{ + u32 val; + int error; + + error = device_property_read_u32(dev, property, &val); + if (error) { + *value = default_value; + return false; + } + + *value = val; + return true; +} + +static void touchscreen_set_params(struct input_dev *dev, + unsigned long axis, + int min, int max, int fuzz) +{ + struct input_absinfo *absinfo; + + if (!test_bit(axis, dev->absbit)) { + dev_warn(&dev->dev, + "Parameters are specified but the axis %lu is not set up\n", + axis); + return; + } + + absinfo = &dev->absinfo[axis]; + absinfo->minimum = min; + absinfo->maximum = max; + absinfo->fuzz = fuzz; +} + +/** + * touchscreen_parse_properties - parse common touchscreen properties + * @input: input device that should be parsed + * @multitouch: specifies whether parsed properties should be applied to + * single-touch or multi-touch axes + * @prop: pointer to a struct touchscreen_properties into which to store + * axis swap and invert info for use with touchscreen_report_x_y(); + * or %NULL + * + * This function parses common properties for touchscreens and sets up the + * input device accordingly. The function keeps previously set up default + * values if no value is specified. + */ +void touchscreen_parse_properties(struct input_dev *input, bool multitouch, + struct touchscreen_properties *prop) +{ + struct device *dev = input->dev.parent; + struct input_absinfo *absinfo; + unsigned int axis, axis_x, axis_y; + unsigned int minimum, maximum, fuzz; + bool data_present; + + input_alloc_absinfo(input); + if (!input->absinfo) + return; + + axis_x = multitouch ? ABS_MT_POSITION_X : ABS_X; + axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y; + + data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x", + input_abs_get_min(input, axis_x), + &minimum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x", + input_abs_get_max(input, + axis_x) + 1, + &maximum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x", + input_abs_get_fuzz(input, axis_x), + &fuzz); + if (data_present) + touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz); + + data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y", + input_abs_get_min(input, axis_y), + &minimum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y", + input_abs_get_max(input, + axis_y) + 1, + &maximum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y", + input_abs_get_fuzz(input, axis_y), + &fuzz); + if (data_present) + touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz); + + axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE; + data_present = touchscreen_get_prop_u32(dev, + "touchscreen-max-pressure", + input_abs_get_max(input, axis), + &maximum); + data_present |= touchscreen_get_prop_u32(dev, + "touchscreen-fuzz-pressure", + input_abs_get_fuzz(input, axis), + &fuzz); + if (data_present) + touchscreen_set_params(input, axis, 0, maximum, fuzz); + + if (!prop) + return; + + prop->max_x = input_abs_get_max(input, axis_x); + prop->max_y = input_abs_get_max(input, axis_y); + + prop->invert_x = + device_property_read_bool(dev, "touchscreen-inverted-x"); + if (prop->invert_x) { + absinfo = &input->absinfo[axis_x]; + absinfo->maximum -= absinfo->minimum; + absinfo->minimum = 0; + } + + prop->invert_y = + device_property_read_bool(dev, "touchscreen-inverted-y"); + if (prop->invert_y) { + absinfo = &input->absinfo[axis_y]; + absinfo->maximum -= absinfo->minimum; + absinfo->minimum = 0; + } + + prop->swap_x_y = + device_property_read_bool(dev, "touchscreen-swapped-x-y"); + if (prop->swap_x_y) + swap(input->absinfo[axis_x], input->absinfo[axis_y]); +} +EXPORT_SYMBOL(touchscreen_parse_properties); + +static void +touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop, + unsigned int *x, unsigned int *y) +{ + if (prop->invert_x) + *x = prop->max_x - *x; + + if (prop->invert_y) + *y = prop->max_y - *y; + + if (prop->swap_x_y) + swap(*x, *y); +} + +/** + * touchscreen_set_mt_pos - Set input_mt_pos coordinates + * @pos: input_mt_pos to set coordinates of + * @prop: pointer to a struct touchscreen_properties + * @x: X coordinate to store in pos + * @y: Y coordinate to store in pos + * + * Adjust the passed in x and y values applying any axis inversion and + * swapping requested in the passed in touchscreen_properties and store + * the result in a struct input_mt_pos. + */ +void touchscreen_set_mt_pos(struct input_mt_pos *pos, + const struct touchscreen_properties *prop, + unsigned int x, unsigned int y) +{ + touchscreen_apply_prop_to_x_y(prop, &x, &y); + pos->x = x; + pos->y = y; +} +EXPORT_SYMBOL(touchscreen_set_mt_pos); + +/** + * touchscreen_report_pos - Report touchscreen coordinates + * @input: input_device to report coordinates for + * @prop: pointer to a struct touchscreen_properties + * @x: X coordinate to report + * @y: Y coordinate to report + * @multitouch: Report coordinates on single-touch or multi-touch axes + * + * Adjust the passed in x and y values applying any axis inversion and + * swapping requested in the passed in touchscreen_properties and then + * report the resulting coordinates on the input_dev's x and y axis. + */ +void touchscreen_report_pos(struct input_dev *input, + const struct touchscreen_properties *prop, + unsigned int x, unsigned int y, + bool multitouch) +{ + touchscreen_apply_prop_to_x_y(prop, &x, &y); + input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x); + input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y); +} +EXPORT_SYMBOL(touchscreen_report_pos); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Helper functions for touchscreens and other devices"); -- cgit v1.3.1