Star, Your change looks good. Thanks/Ray
> -----Original Message----- > From: Zeng, Star > Sent: Tuesday, July 18, 2017 4:39 PM > To: Heyi Guo <[email protected]>; [email protected]; Ni, Ruiyu > <[email protected]>; Laszlo Ersek ([email protected]) > <[email protected]> > Cc: Zeng, Star <[email protected]> > Subject: RE: [edk2] MdeModulePkg/SerialDxe: Inconsistent timeout > processing in SerialRead > > 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; > } > > _______________________________________________ > edk2-devel mailing list > [email protected] > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
