From: Aleksa Savic <savicaleksa83@xxxxxxxxx> commit 56b930dcd88c2adc261410501c402c790980bdb5 upstream. Add a 200ms delay after sending a ctrl report to Quadro, Octo, D5 Next and Aquaero to give them enough time to process the request and save the data to memory. Otherwise, under heavier userspace loads where multiple sysfs entries are usually set in quick succession, a new ctrl report could be requested from the device while it's still processing the previous one and fail with -EPIPE. The delay is only applied if two ctrl report operations are near each other in time. Reported by a user on Github [1] and tested by both of us. [1] https://github.com/aleksamagicka/aquacomputer_d5next-hwmon/issues/82 Fixes: 752b927951ea ("hwmon: (aquacomputer_d5next) Add support for Aquacomputer Octo") Signed-off-by: Aleksa Savic <savicaleksa83@xxxxxxxxx> Link: https://lore.kernel.org/r/20230807172004.456968-1-savicaleksa83@xxxxxxxxx Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hwmon/aquacomputer_d5next.c | 37 +++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) --- a/drivers/hwmon/aquacomputer_d5next.c +++ b/drivers/hwmon/aquacomputer_d5next.c @@ -13,9 +13,11 @@ #include <linux/crc16.h> #include <linux/debugfs.h> +#include <linux/delay.h> #include <linux/hid.h> #include <linux/hwmon.h> #include <linux/jiffies.h> +#include <linux/ktime.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/seq_file.h> @@ -61,6 +63,8 @@ static const char *const aqc_device_name #define CTRL_REPORT_ID 0x03 #define AQUAERO_CTRL_REPORT_ID 0x0b +#define CTRL_REPORT_DELAY 200 /* ms */ + /* The HID report that the official software always sends * after writing values, currently same for all devices */ @@ -496,6 +500,9 @@ struct aqc_data { int secondary_ctrl_report_size; u8 *secondary_ctrl_report; + ktime_t last_ctrl_report_op; + int ctrl_report_delay; /* Delay between two ctrl report operations, in ms */ + int buffer_size; u8 *buffer; int checksum_start; @@ -577,17 +584,35 @@ static int aqc_aquastreamxt_convert_fan_ return 0; } +static void aqc_delay_ctrl_report(struct aqc_data *priv) +{ + /* + * If previous read or write is too close to this one, delay the current operation + * to give the device enough time to process the previous one. + */ + if (priv->ctrl_report_delay) { + s64 delta = ktime_ms_delta(ktime_get(), priv->last_ctrl_report_op); + + if (delta < priv->ctrl_report_delay) + msleep(priv->ctrl_report_delay - delta); + } +} + /* Expects the mutex to be locked */ static int aqc_get_ctrl_data(struct aqc_data *priv) { int ret; + aqc_delay_ctrl_report(priv); + memset(priv->buffer, 0x00, priv->buffer_size); ret = hid_hw_raw_request(priv->hdev, priv->ctrl_report_id, priv->buffer, priv->buffer_size, HID_FEATURE_REPORT, HID_REQ_GET_REPORT); if (ret < 0) ret = -ENODATA; + priv->last_ctrl_report_op = ktime_get(); + return ret; } @@ -597,6 +622,8 @@ static int aqc_send_ctrl_data(struct aqc int ret; u16 checksum; + aqc_delay_ctrl_report(priv); + /* Checksum is not needed for Aquaero */ if (priv->kind != aquaero) { /* Init and xorout value for CRC-16/USB is 0xffff */ @@ -612,12 +639,16 @@ static int aqc_send_ctrl_data(struct aqc ret = hid_hw_raw_request(priv->hdev, priv->ctrl_report_id, priv->buffer, priv->buffer_size, HID_FEATURE_REPORT, HID_REQ_SET_REPORT); if (ret < 0) - return ret; + goto record_access_and_ret; /* The official software sends this report after every change, so do it here as well */ ret = hid_hw_raw_request(priv->hdev, priv->secondary_ctrl_report_id, priv->secondary_ctrl_report, priv->secondary_ctrl_report_size, HID_FEATURE_REPORT, HID_REQ_SET_REPORT); + +record_access_and_ret: + priv->last_ctrl_report_op = ktime_get(); + return ret; } @@ -1443,6 +1474,7 @@ static int aqc_probe(struct hid_device * priv->buffer_size = AQUAERO_CTRL_REPORT_SIZE; priv->temp_ctrl_offset = AQUAERO_TEMP_CTRL_OFFSET; + priv->ctrl_report_delay = CTRL_REPORT_DELAY; priv->temp_label = label_temp_sensors; priv->virtual_temp_label = label_virtual_temp_sensors; @@ -1466,6 +1498,7 @@ static int aqc_probe(struct hid_device * priv->temp_ctrl_offset = D5NEXT_TEMP_CTRL_OFFSET; priv->buffer_size = D5NEXT_CTRL_REPORT_SIZE; + priv->ctrl_report_delay = CTRL_REPORT_DELAY; priv->power_cycle_count_offset = D5NEXT_POWER_CYCLES; @@ -1516,6 +1549,7 @@ static int aqc_probe(struct hid_device * priv->temp_ctrl_offset = OCTO_TEMP_CTRL_OFFSET; priv->buffer_size = OCTO_CTRL_REPORT_SIZE; + priv->ctrl_report_delay = CTRL_REPORT_DELAY; priv->power_cycle_count_offset = OCTO_POWER_CYCLES; @@ -1543,6 +1577,7 @@ static int aqc_probe(struct hid_device * priv->temp_ctrl_offset = QUADRO_TEMP_CTRL_OFFSET; priv->buffer_size = QUADRO_CTRL_REPORT_SIZE; + priv->ctrl_report_delay = CTRL_REPORT_DELAY; priv->flow_pulses_ctrl_offset = QUADRO_FLOW_PULSES_CTRL_OFFSET; priv->power_cycle_count_offset = QUADRO_POWER_CYCLES;
