On 19.09.2019 18:24, Oleksandr Natalenko wrote:
[ +9,979664] mt76x2e 0000:01:00.0: Firmware Version: 0.0.00
[ +0,000014] mt76x2e 0000:01:00.0: Build: 1
[ +0,000010] mt76x2e 0000:01:00.0: Build Time: 201507311614____
[ +0,018017] mt76x2e 0000:01:00.0: Firmware running!
[ +0,001101] ieee80211 phy4: Hardware restart was requested
IIUC, this happens due to watchdog. I think the following applies.
Watchdog is started here:
=== mt76x02_util.c
130 void mt76x02_init_device(struct mt76x02_dev *dev)
131 {
...
155 INIT_DELAYED_WORK(&dev->wdt_work, mt76x02_wdt_work);
===
It checks for TX hang here:
=== mt76x02_mmio.c
557 void mt76x02_wdt_work(struct work_struct *work)
558 {
...
562 mt76x02_check_tx_hang(dev);
===
Conditions:
=== mt76x02_mmio.c
530 static void mt76x02_check_tx_hang(struct mt76x02_dev *dev)
531 {
532 if (mt76x02_tx_hang(dev)) {
533 if (++dev->tx_hang_check >= MT_TX_HANG_TH)
534 goto restart;
535 } else {
536 dev->tx_hang_check = 0;
537 }
538
539 if (dev->mcu_timeout)
540 goto restart;
541
542 return;
543
544 restart:
545 mt76x02_watchdog_reset(dev);
===
Actual check:
=== mt76x02_mmio.c
367 static bool mt76x02_tx_hang(struct mt76x02_dev *dev)
368 {
369 u32 dma_idx, prev_dma_idx;
370 struct mt76_queue *q;
371 int i;
372
373 for (i = 0; i < 4; i++) {
374 q = dev->mt76.q_tx[i].q;
375
376 if (!q->queued)
377 continue;
378
379 prev_dma_idx = dev->mt76.tx_dma_idx[i];
380 dma_idx = readl(&q->regs->dma_idx);
381 dev->mt76.tx_dma_idx[i] = dma_idx;
382
383 if (prev_dma_idx == dma_idx)
384 break;
385 }
386
387 return i < 4;
388 }
===
(I don't quite understand what it does here; why 4? does each device
have 4 queues? maybe, my does not? I guess this is where watchdog is
triggered, though, because otherwise I'd see mcu_timeout message like
"MCU message %d (seq %d) timed out\n")
Once it detects TX hang, the reset is triggered:
=== mt76x02_mmio.c
446 static void mt76x02_watchdog_reset(struct mt76x02_dev *dev)
447 {
...
485 if (restart)
486 mt76_mcu_restart(dev);
===
mt76_mcu_restart() is just a define for this series here:
=== mt76.h
555 #define mt76_mcu_restart(dev, ...)
(dev)->mt76.mcu_ops->mcu_restart(&((dev)->mt76))
===
Actual OP:
=== mt76x2/pci_mcu.c
188 int mt76x2_mcu_init(struct mt76x02_dev *dev)
189 {
190 static const struct mt76_mcu_ops mt76x2_mcu_ops = {
191 .mcu_restart = mt76pci_mcu_restart,
192 .mcu_send_msg = mt76x02_mcu_msg_send,
193 };
===
This triggers loading the firmware:
=== mt76x2/pci_mcu.c
168 static int
169 mt76pci_mcu_restart(struct mt76_dev *mdev)
170 {
...
179 ret = mt76pci_load_firmware(dev);
===
which does the printout I observe:
=== mt76x2/pci_mcu.c
91 static int
92 mt76pci_load_firmware(struct mt76x02_dev *dev)
93 {
...
156 dev_info(dev->mt76.dev, "Firmware running!\n");
===
Too bad it doesn't show the actual watchdog message, IOW, why the reset
happens. I guess I will have to insert some pr_infos here and there.
Does it make sense? Any ideas why this can happen?
More info on the device during boot:
===
[ +0,333233] mt76x2e 0000:01:00.0: enabling device (0000 -> 0002)
[ +0,000571] mt76x2e 0000:01:00.0: ASIC revision: 76120044
[ +0,017806] mt76x2e 0000:01:00.0: ROM patch build: 20141115060606a
===
--
Oleksandr Natalenko (post-factum)
