[PATCH] Revert "serial: 8250_dw: Fix runtime PM handling"

Guenter Roeck
2018-10-02T04:42:50Z

This reverts commit d76c74387e1c978b6c5524a146ab0f3f72206f98.

While commit d76c74387e1c ("serial: 8250_dw: Fix runtime PM handling")
fixes runtime PM handling when using kgdb, it introduces a traceback for
everyone else.

BUG: sleeping function called from invalid context at
/mnt/host/source/src/third_party/kernel/next/drivers/base/power/runtime.c:1034
in_atomic(): 1, irqs_disabled(): 1, pid: 1, name: swapper/0
7 locks held by swapper/0/1:
#0: 000000005ec5bc72 (&dev->mutex){....}, at: __driver_attach+0xb5/0x12b
#1: 000000005d5fa9e5 (&dev->mutex){....}, at: __device_attach+0x3e/0x15b
#2: 0000000047e93286 (serial_mutex){+.+.}, at: serial8250_register_8250_port+0x51/0x8bb
#3: 000000003b328f07 (port_mutex){+.+.}, at: uart_add_one_port+0xab/0x8b0
#4: 00000000fa313d4d (&port->mutex){+.+.}, at: uart_add_one_port+0xcc/0x8b0
#5: 00000000090983ca (console_lock){+.+.}, at: vprintk_emit+0xdb/0x217
#6: 00000000c743e583 (console_owner){-...}, at: console_unlock+0x211/0x60f
irq event stamp: 735222
__down_trylock_console_sem+0x4a/0x84
console_unlock+0x338/0x60f
__do_softirq+0x4a4/0x50d
irq_exit+0x64/0xe2
CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc5 #6
Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.286.0 03/15/2017
Call Trace:
dump_stack+0x7d/0xbd
___might_sleep+0x238/0x259
__pm_runtime_resume+0x4e/0xa4
? serial8250_rpm_get+0x2e/0x44
serial8250_console_write+0x44/0x301
? lock_acquire+0x1b8/0x1fa
console_unlock+0x577/0x60f
vprintk_emit+0x1f0/0x217
printk+0x52/0x6e
register_console+0x43b/0x524
uart_add_one_port+0x672/0x8b0
? set_io_from_upio+0x150/0x162
serial8250_register_8250_port+0x825/0x8bb
dw8250_probe+0x80c/0x8b0
? dw8250_serial_inq+0x8e/0x8e
? dw8250_check_lcr+0x108/0x108
? dw8250_runtime_resume+0x5b/0x5b
? dw8250_serial_outq+0xa1/0xa1
? dw8250_remove+0x115/0x115
platform_drv_probe+0x76/0xc5
really_probe+0x1f1/0x3ee
? driver_allows_async_probing+0x5d/0x5d
driver_probe_device+0xd6/0x112
? driver_allows_async_probing+0x5d/0x5d
bus_for_each_drv+0xbe/0xe5
__device_attach+0xdd/0x15b
bus_probe_device+0x5a/0x10b
device_add+0x501/0x894
? _raw_write_unlock+0x27/0x3a
platform_device_add+0x224/0x2b7
mfd_add_device+0x718/0x75b
? __kmalloc+0x144/0x16a
? mfd_add_devices+0x38/0xdb
mfd_add_devices+0x9b/0xdb
intel_lpss_probe+0x7d4/0x8ee
intel_lpss_pci_probe+0xac/0xd4
pci_device_probe+0x101/0x18e
...

Revert the offending patch until a more comprehensive solution
is available.

Cc: Tony Lindgren <tony@atomide.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Fixes: d76c74387e1c ("serial: 8250_dw: Fix runtime PM handling")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/tty/serial/8250/8250_dw.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index fa8dcb470640..d31b975dd3fd 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -630,10 +630,6 @@ static int dw8250_probe(struct platform_device *pdev)
if (!data->skip_autocfg)
dw8250_setup_port(p);

-#ifdef CONFIG_PM
- uart.capabilities |= UART_CAP_RPM;
-#endif
-
/* If we have a valid fifosize, try hooking up DMA */
if (p->fifosize) {
data->dma.rxconf.src_maxburst = p->fifosize / 4;
--
2.7.4