In "11.8 Serial I/O Protocol", UEFI 2.5 requires:
The default attributes for all UART-style serial device interfaces are:
(a) 115,200 baud,
(b) a 1 byte receive FIFO,
(c) a 1,000,000 microsecond timeout per character,
(d) no parity,
(e) 8 data bits,
(f) and 1 stop bit.
It also says, about the EFI_SERIAL_IO_MODE.ControlMask member:
(g) A mask of the Control bits that the device supports. The device must
always support the Input Buffer Empty control bit.
SerialDxe complies with requirement (b) via hard-coded constants. It
complies with requirements (a), (d), (e) and (f) through PCD defaults (see
MdePkg/MdePkg.dec):
(a) 115,200 baud:
gEfiMdePkgTokenSpaceGuid.PcdUartDefaultBaudRate|115200|UINT64|0x00000020
(d) no parity:
# 1 - No Parity.<BR>
gEfiMdePkgTokenSpaceGuid.PcdUartDefaultParity|1|UINT8|0x00000022
(e) 8 data bits:
gEfiMdePkgTokenSpaceGuid.PcdUartDefaultDataBits|8|UINT8|0x00000021
(f) 1 stop bit:
# 1 - One Stop Bit.<BR>
gEfiMdePkgTokenSpaceGuid.PcdUartDefaultStopBits|1|UINT8|0x00000023
SerialDxe does not comply with requirements (c) and (g). In this patch, we
fix (c), and leave (g) for later.
Cc: Ard Biesheuvel <[email protected]>
Cc: Ryan Harkin <[email protected]>
Cc: Leif Lindholm <[email protected]>
Cc: Star Zeng <[email protected]>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <[email protected]>
---
MdeModulePkg/Universal/SerialDxe/SerialIo.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/MdeModulePkg/Universal/SerialDxe/SerialIo.c
b/MdeModulePkg/Universal/SerialDxe/SerialIo.c
index 489a4a2..f5b3064 100644
--- a/MdeModulePkg/Universal/SerialDxe/SerialIo.c
+++ b/MdeModulePkg/Universal/SerialDxe/SerialIo.c
@@ -185,7 +185,7 @@ EFI_SERIAL_IO_MODE mSerialIoMode = {
// value field set in SerialDxeInitialize()?
//--------- ------------------- -----------------------------
0, // ControlMask
- 0, // Timeout
+ 1000 * 1000, // Timeout
0, // BaudRate yes
1, // ReceiveFifoDepth
0, // DataBits yes
@@ -237,7 +237,7 @@ SerialReset (
// Set the Serial I/O mode
//
This->Mode->ReceiveFifoDepth = 1;
- This->Mode->Timeout = 0;
+ This->Mode->Timeout = 1000 * 1000;
This->Mode->BaudRate = PcdGet64 (PcdUartDefaultBaudRate);
This->Mode->DataBits = (UINT32) PcdGet8 (PcdUartDefaultDataBits);
This->Mode->Parity = (UINT32) PcdGet8 (PcdUartDefaultParity);
--
1.8.3.1
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