Hi Graeme,
Le 31/01/2018 à 15:21, Graeme Gregory a écrit :
On Wed, Oct 11, 2017 at 10:32:14AM +0200, Frédéric Danis wrote:
UART devices is expected to be enumerated by SerDev subsystem.
During ACPI scan, serial devices behind SPI, I2C or UART buses are not
enumerated, allowing them to be enumerated by their respective parents.
Rename *spi_i2c_slave* to *serial_bus_slave* as this will be used for serial
devices on serial buses (SPI, I2C or UART).
On Macs an empty ResourceTemplate is returned for uart slaves.
Instead the device properties "baud", "parity", "dataBits", "stopBits" are
provided. Add a check for "baud" in acpi_is_serial_bus_slave().
This patch appears to break UART probing in ACPI on xgene based
plaforms.
The appropriate chunks of DSDT.
Device (_SB.AHBC)
{
OperationRegion (SRST, SystemMemory, 0x1F2AC000, 0x04)
OperationRegion (CLKE, SystemMemory, 0x1F2AC004, 0x04)
OperationRegion (SRRM, SystemMemory, 0x1F2AD070, 0x04)
OperationRegion (RD2F, SystemMemory, 0x1F2AE014, 0x04)
...
Device (UAR0)
{
Name (_HID, "APMC0D08") // _HID: Hardware ID
Name (_DDN, "UAR0") // _DDN: DOS Device Name
Name (_UID, "UAR0") // _UID: Unique ID
Name (_STR, Unicode ("APM88xxxx UART0 Controller")) // _STR: Description String
Name (_ADR, 0x1C021000) // _ADR: Address
Name (_CID, "NS16550A") // _CID: Compatible ID
...
Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
{
Memory32Fixed (ReadWrite,
0x1C021000, // Address Base
0x00000100, // Address Length
)
UartSerialBusV2 (0x00002580, DataBitsEight, StopBitsOne,
0x00, LittleEndian, ParityTypeNone, FlowControlHardware,
0x0010, 0x0010, "UAR0",
0x00, ResourceConsumer, , Exclusive,
)
Interrupt (ResourceProducer, Level, ActiveHigh, Exclusive, ,, )
{
0x0000006D,
}
})
This seems to be related to
https://bugzilla.redhat.com/show_bug.cgi?id=1531140
Am I correct?
The SerDev support should allow UART to appear as tty device if not used
by an underlying component (cf. tty_port_register_device_attr() in
drivers/tty/tty_port.c).
AFAIU, there is no internal device attached to this serial port.
Is it possible to get complete ACPI DSDT?
Is SerDev enabled on this device?
Boot logs with SerDev debug traces enabled can be useful to understand
what happens.
Regards,
Fred
--
Frédéric Danis Embedded Linux Consultant
frederic.danis.oss@xxxxxxxxx
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