No problem at all and thanks a lot for fixing the issue :)
Gary (Heyi Guo)
在 8/4/2017 4:05 PM, Zeng, Star 写道:
Oh, sorry, I forgot it because of busying on other things. I will post it soon.
Thanks for your reminder.
Star
-----Original Message-----
From: Heyi Guo [mailto:[email protected]]
Sent: Friday, August 4, 2017 4:03 PM
To: Zeng, Star <[email protected]>; [email protected]; Ni, Ruiyu
<[email protected]>; Laszlo Ersek ([email protected]) <[email protected]>
Subject: Re: [edk2] MdeModulePkg/SerialDxe: Inconsistent timeout processing in
SerialRead
Hi Star,
The patch works well on our platform. Would you merge it to EDK2 main stream or
do you like me to post it to the mailing-list?
Thanks and regards,
Gary (Heyi Guo)
在 7/18/2017 6:59 PM, Heyi Guo 写道:
Hi Star,
I think your proposed patch is fine.
Thanks.
Gary (Heyi Guo)
在 7/18/2017 4:39 PM, Zeng, Star 写道:
Gary,
SerialDxe is a wrapper of SerialPortLib to produce serial io protocol.
If let SerialDxe to handle the TimeOut, seemingly it can only check
SerialPortPoll() and read data by SerialPortRead() one byte by one
byte, for example like below.
Do you have any proposed patch?
Ray and Laszlo,
Do you have any comments?
====================
debf0d1b85e7a30defd29838abb20a44dd9ec69b
MdeModulePkg/Universal/SerialDxe/SerialIo.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/MdeModulePkg/Universal/SerialDxe/SerialIo.c
b/MdeModulePkg/Universal/SerialDxe/SerialIo.c
index d2383e56dd8f..b05603d7f3b5 100644
--- a/MdeModulePkg/Universal/SerialDxe/SerialIo.c
+++ b/MdeModulePkg/Universal/SerialDxe/SerialIo.c
@@ -465,11 +465,25 @@ SerialRead (
)
{
UINTN Count;
+ UINTN TimeOut;
Count = 0;
- if (SerialPortPoll ()) {
- Count = SerialPortRead (Buffer, *BufferSize);
+ while (Count < *BufferSize) {
+ TimeOut = 0;
+ while (TimeOut < mSerialIoMode.TimeOut) {
+ if (SerialPortPoll ()) {
+ break;
+ }
+ gBS->Stall (10);
+ TimeOut += 10;
+ }
+ if (TimeOut >= mSerialIoMode.TimeOut) {
+ break;
+ }
+ SerialPortRead (Buffer, 1);
+ Count++;
+ Buffer = (VOID *) ((UINT8 *) Buffer + 1);
}
if (Count != *BufferSize) {
====================
Thanks,
Star
-----Original Message-----
From: edk2-devel [mailto:[email protected]] On Behalf
Of Heyi Guo
Sent: Monday, July 17, 2017 12:23 PM
To: [email protected]
Subject: [edk2] MdeModulePkg/SerialDxe: Inconsistent timeout
processing in SerialRead
Hi Folks,
In SerialRead function in
MdeModulePkg/Universal/SerialDxe/SerialIo.c,
it seems the timeout processing in SerialRead is not consistent.
Since SerialPortPoll only checks the status of serial port and
returns immediately, and SerialPortRead does not really implement a
time out mechanism and will always wait for enough input, it will
cause below
results:
1. If there is no serial input at all, this interface will return
timeout immediately without any waiting;
2. If there is A characters in serial port FIFO, and caller requires
A+1 characters, it will wait until a new input is coming and timeout
will not really occur.
As SerialPortLib is a simple library implementation, I think it is
better to improve SerialIoDxe driver instead of SerialPortLib.
Please let me know your comments about this.
Thanks and regards,
Gary (Heyi Guo)
EFI_STATUS
EFIAPI
SerialRead (
IN EFI_SERIAL_IO_PROTOCOL *This,
IN OUT UINTN *BufferSize,
OUT VOID *Buffer
)
{
UINTN Count;
Count = 0;
if (SerialPortPoll ()) {
Count = SerialPortRead (Buffer, *BufferSize);
}
if (Count != *BufferSize) {
*BufferSize = Count;
return EFI_TIMEOUT;
}
return EFI_SUCCESS;
}
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