[Spice-devel] [PATCH qxl-wddm-dod 03/26] Add printer class to dump debug print statements to kernel debugger output

[Frediano Ziglio]

> 
> From: Sandy Stutsman <sstutsma at redhat.com>
> 
> Allows the usage of Kd_IHVVIDEO_Mask to control print level while debugging
> 
> Signed-off-by: Sameeh Jubran <sameeh at daynix.com>
> ---
>  qxldod/driver.cpp | 24 +++++++++++++++++++++++-
>  qxldod/driver.h   | 20 ++++++++++++++++----
>  2 files changed, 39 insertions(+), 5 deletions(-)
> 
> diff --git a/qxldod/driver.cpp b/qxldod/driver.cpp
> index 4d1913c..d9946aa 100755
> --- a/qxldod/driver.cpp
> +++ b/qxldod/driver.cpp
> @@ -667,7 +667,29 @@ void DebugPrintFunc(const char *format, ...)
>      va_start(list, format);
>      vDbgPrintEx(DPFLTR_DEFAULT_ID, 9 | DPFLTR_MASK, format, list);
>  }
> +
> +kd_debug_printer::kd_debug_printer(ULONG level)
> +{
> +    static const ULONG xlate[] = { 0, 0, 1, 2, 3 };
> +    if (!level || level > 5) {
> +        _level = 0xffffffff;
> +
> +    }
> +    else {
> +        _level = xlate[level - 1];
> +    }
> +}
> +
> +void kd_debug_printer::print(const char * fmt, ...)
> +{
> +    if (_level == 0xffffffff) {
> +        return;
> +    }
> +    va_list list;
> +    va_start(list, fmt);
> +    vDbgPrintEx(DPFLTR_IHVVIDEO_ID, _level, fmt, list);
> +    va_end(list);
> +}
>  #endif
>  
>  #pragma code_seg(pop) // End Non-Paged Code
> -
> diff --git a/qxldod/driver.h b/qxldod/driver.h
> index e64c098..752f8e4 100755
> --- a/qxldod/driver.h
> +++ b/qxldod/driver.h
> @@ -208,15 +208,27 @@ DodSystemDisplayWrite(
>      _In_  UINT  PositionY);
>  
>  #if DBG
> +class kd_debug_printer
> +{
> +public:
> +    kd_debug_printer(ULONG level);
> +    void print(const char * fmt, ...);
> +private:
> +    ULONG _level;
> + };
>  
>  extern int nDebugLevel;
>  void DebugPrintFuncSerial(const char *format, ...);
>  
> -void DebugPrintFunc(const char *format, ...);
> +void DebugPrintFunc(const char *format, ...);
> +
> +#define DbgPrint(level, line)           \
> +    if (level > nDebugLevel) {}         \
> +    else {                              \
> +       DebugPrintFuncSerial line;       \
> +     }                                  \
> +     kd_debug_printer(level).print line
>  
> -#define DbgPrint(level, line) \
> -    if (level > nDebugLevel) {} \
> -    else DebugPrintFuncSerial line
>  #else
>  #define DbgPrint(level, line)
>  #endif

This can be done much easier with variadic macros and a simple function.

void DebugPrint(int level, const char *fmt, ...);

#define DbgExpandArguments(...) __VA_ARGS__
#define DbgPrint(level, line) do { \
    if (level <= nDebugLevel) DebugPrintFuncSerial line; \
    DebugPrint(level, DbgExpandArguments line); \
} while(0)


and the definition


void DebugPrint(int level, const char *fmt, ...)
{
   static const ULONG xlate[] = { 0, 0, 1, 2, 3 };
   if (level <= 0 || level > 5)
       return;

   va_list list;
   va_start(list, fmt);
   vDbgPrintEx(DPFLTR_IHVVIDEO_ID, xlate[level - 1], fmt, list);
   va_end(list);
}


Cannot test but I can see the print is duplicated to DebugPrintFuncSerial
and vDbgPrintEx. Is this wanted?

Frediano