Re: [Bugme-new] [Bug 12056] New: the serial device(ttyS0) is unuseable after booting the kernel

[Shan Wei <shanwei@cn.fujitsu.com>]

五島殿

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Andrew Morton says:
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
> 
> On Mon, 17 Nov 2008 18:44:44 -0800 (PST) bugme-daemon@bugzilla.kernel.org wrote:
> 
>> http://bugzilla.kernel.org/show_bug.cgi?id=12056
>>
>>            Summary: the serial device(ttyS0) is unuseable after booting the
>>                     kernel
>>            Product: ACPI
>>            Version: 2.5
>>      KernelVersion: 2.6.28-rc3
>>           Platform: All
>>         OS/Version: Linux
>>               Tree: Mainline
>>             Status: NEW
>>           Severity: blocking
>>           Priority: P1
>>          Component: ACPICA-Core
>>         AssignedTo: acpi_acpica-core@kernel-bugs.osdl.org
>>         ReportedBy: shanwei@cn.fujitsu.com
>>
>>
>> Latest working kernel version:2.6.28-rc3
>> Earliest failing kernel version:2.6.28-rc1
>> Distribution:
>> Hardware Environment:fujitsu's PG
>> Software Environment:
>> Problem Description:
>>
>>   When i switch to the kernel of 2.6.28-rc3, the serial device 
>> (ttyS0) is unused. But on 2.6.27, it's ok. 
>>
>> On 2.6.28-rc3:
>> [root@DaVid compiler]# setserial /dev/ttyS0
>> /dev/ttyS0, UART: unknown, Port: 0x03f8, IRQ: 4
>>
>> On 2.6.27:
>> [root@DaVid compiler]# setserial /dev/ttyS0
>> /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
>>
>>   The problem comes from this patch 39a0ad871000d2a016a4fa113a6e53d22aabf25d___
>> For the device that is not present but functional, it unload the driver for the
>> device. 
>>   In the following patch, I try to fix it whthout check the present bit when
>> adding device. After applied the patch, the serial device is useable again.
>>
>> diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
>> index 383e47c..bcc731b 100644
>> --- a/drivers/pnp/pnpacpi/core.c
>> +++ b/drivers/pnp/pnpacpi/core.c
>> @@ -154,7 +154,7 @@ static int __init pnpacpi_add_device(struct acpi_device
>> *device)
>>          */
>>         status = acpi_get_handle(device->handle, "_CRS", &temp);
>>         if (ACPI_FAILURE(status) || !ispnpidacpi(acpi_device_hid(device)) ||
>> -           is_exclusive_device(device) || (!device->status.present))
>> +           is_exclusive_device(device))
>>                 return 0;
>>
>>         dev = pnp_alloc_dev(&pnpacpi_protocol, num, acpi_device_hid(device));
>>
>> Steps to reproduce:
>> 1)build the kernel of 2.6.28-rc3;
>> 2)check the device with ___setserial /dev/ttyS0___
>>
>>
> 
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