X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=MdeModulePkg%2FUniversal%2FSerialDxe%2FSerialIo.c;h=ee10ec7e05eadcb1a5ffc2fc3bd8d0a8d678851e;hb=13d378fc82d4c10eff48bec383cd679cec6c4fdb;hp=ebcd92726314a83935c56c266bd694314c56ddec;hpb=91cc526b15ffbbbdec5a57906596f37e059f80be;p=mirror_edk2.git

diff --git a/MdeModulePkg/Universal/SerialDxe/SerialIo.c b/MdeModulePkg/Universal/SerialDxe/SerialIo.c
index ebcd927263..ee10ec7e05 100644
--- a/MdeModulePkg/Universal/SerialDxe/SerialIo.c
+++ b/MdeModulePkg/Universal/SerialDxe/SerialIo.c
@@ -66,8 +66,9 @@ SerialReset (
                            value of DefaultStopBits will use the device's default number of
                            stop bits.
 
-  @retval EFI_SUCCESS      The device was reset.
-  @retval EFI_DEVICE_ERROR The serial device could not be reset.
+  @retval EFI_SUCCESS           The device was reset.
+  @retval EFI_INVALID_PARAMETER One or more attributes has an unsupported value.
+  @retval EFI_DEVICE_ERROR      The serial device is not functioning correctly.
 
 **/
 EFI_STATUS
@@ -264,8 +265,9 @@ SerialReset (
                            value of DefaultStopBits will use the device's default number of
                            stop bits.
 
-  @retval EFI_SUCCESS      The device was reset.
-  @retval EFI_DEVICE_ERROR The serial device could not be reset.
+  @retval EFI_SUCCESS           The device was reset.
+  @retval EFI_INVALID_PARAMETER One or more attributes has an unsupported value.
+  @retval EFI_DEVICE_ERROR      The serial device is not functioning correctly.
 
 **/
 EFI_STATUS
@@ -280,12 +282,54 @@ SerialSetAttributes (
   IN EFI_STOP_BITS_TYPE     StopBits
   )
 {
-  EFI_STATUS    Status;
-  EFI_TPL       Tpl;
+  EFI_STATUS                Status;
+  EFI_TPL                   Tpl;
+  UINT64                    OriginalBaudRate;
+  UINT32                    OriginalReceiveFifoDepth;
+  UINT32                    OriginalTimeout;
+  EFI_PARITY_TYPE           OriginalParity;
+  UINT8                     OriginalDataBits;
+  EFI_STOP_BITS_TYPE        OriginalStopBits;
 
+  //
+  // Preserve the original input values in case
+  // SerialPortSetAttributes() updates the input/output
+  // parameters even on error.
+  //
+  OriginalBaudRate = BaudRate;
+  OriginalReceiveFifoDepth = ReceiveFifoDepth;
+  OriginalTimeout = Timeout;
+  OriginalParity = Parity;
+  OriginalDataBits = DataBits;
+  OriginalStopBits = StopBits;
   Status = SerialPortSetAttributes (&BaudRate, &ReceiveFifoDepth, &Timeout, &Parity, &DataBits, &StopBits);
   if (EFI_ERROR (Status)) {
-    return Status;
+    //
+    // If it is just to set Timeout value and unsupported is returned,
+    // do not return error.
+    //
+    if ((Status == EFI_UNSUPPORTED) &&
+        (This->Mode->Timeout          != OriginalTimeout) &&
+        (This->Mode->ReceiveFifoDepth == OriginalReceiveFifoDepth) &&
+        (This->Mode->BaudRate         == OriginalBaudRate) &&
+        (This->Mode->DataBits         == (UINT32) OriginalDataBits) &&
+        (This->Mode->Parity           == (UINT32) OriginalParity) &&
+        (This->Mode->StopBits         == (UINT32) OriginalStopBits)) {
+      //
+      // Restore to the original input values.
+      //
+      BaudRate = OriginalBaudRate;
+      ReceiveFifoDepth = OriginalReceiveFifoDepth;
+      Timeout = OriginalTimeout;
+      Parity = OriginalParity;
+      DataBits = OriginalDataBits;
+      StopBits = OriginalStopBits;
+      Status = EFI_SUCCESS;
+    } else if (Status == EFI_INVALID_PARAMETER || Status == EFI_UNSUPPORTED) {
+      return EFI_INVALID_PARAMETER;
+    } else {
+      return EFI_DEVICE_ERROR;
+    }
   }
 
   //