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charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit Hi Vidya, On 06-04-2026 11:11, Srinivas, Vidya wrote: > >> -----Original Message----- >> From: Purkait, Soham >> Sent: 06 April 2026 10:27 >> To: Srinivas, Vidya;igt-dev@lists.freedesktop.org; >> Konieczny, Kamil >> Subject: Re: tools/gputop: Fix zero output when stdout is not a terminal >> >> Hi Vidya, >> >> On 02-04-2026 19:15, Vidya Srinivas wrote: >>> When gputop output is redirected to a file or pipe, such as: >>> >>> gputop -n 5 -d 1 > results.txt >> Isn’t only stdout (fd 1) redirected to the file here? >> >> I guess some thing like "echo test | ./gputop" would be returning the default >> value (-1 in this case) for con_h. > Hello, > > Many thanks for the review. > I will update the patch like this. Should be okay? > > if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 && > ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1 && > ioctl(STDERR_FILENO, TIOCGWINSZ, &ws) == -1) { I assume it's better to keep this : "if (ioctl(0, TIOCGWINSZ, &ws) == -1)" as is. As it won't make any  issue if the gputop output is redirected to any file or so (which only involve stdout).  The expression  will only be true when stdin is not a terminal, may be during running gputop in a ci. And Its better to assign the default values to con_w and con_h in main. (please see below) > ws.ws_col = 80; > ws.ws_row = 50; > } > > Regards > Vidya > >>> gputop -n 3 -d 2 | grep rcs >>> >>> ioctl(0, TIOCGWINSZ) fails with -1 since stdin is not a terminal. >>> update_console_size() then returns without setting *w and *h, leaving >>> con_w and con_h at their initial value of -1. >>> >>> The main display loop uses 'if (lines >= con_h) break' to limit output >>> to the terminal height. With con_h = -1, the condition (0 >= -1) is >>> immediately true on the very first line, causing all client output to >>> be silently suppressed. The result is that gputop produces only ANSI >>> clear- screen escape sequences and zero actual data. >>> >>> This affects anyone using gputop in automation, CI pipelines, or any >>> non-interactive context on Linux or Android where output is redirected >>> or piped. >>> >>> Fix this by falling back to a default console size of 80x50 when the >>> ioctl fails, consistent with the existing fallback for serial consoles >>> (where ws_col and ws_row are both 0). >>> >>> Signed-off-by: Vidya Srinivas >>> Reviewed-by: Kamil Konieczny >>> --- >>> tools/gputop.c | 5 ++++- >>> 1 file changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/tools/gputop.c b/tools/gputop.c index >>> 9b2e8cb6f..112ec5ddb 100644 >>> --- a/tools/gputop.c >>> +++ b/tools/gputop.c >>> @@ -505,8 +505,11 @@ static void update_console_size(int *w, int *h) >>> { >>> struct winsize ws = {}; >>> >>> - if (ioctl(0, TIOCGWINSZ, &ws) == -1) >>> + if (ioctl(0, TIOCGWINSZ, &ws) == -1) { >>> + *w = 80; >>> + *h = 50; Imho instead of setting the values (*w = 80;*h = 50) here , it's better to initialize these as default values in main as "int con_w = 80, con_h = 50;" Thanks, Soham >> How about assigning the values during initialization in the main function ? >> >> eg : int con_w = 80, con_h = 50; >> >> Thanks, >> Soham >> >>> return; >>> + } >>> >>> *w = ws.ws_col; >>> *h = ws.ws_row; --------------JYUdJJDykwOkzr5EglfAR9kf Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: 8bit

Hi Vidya,

On 06-04-2026 11:11, Srinivas, Vidya wrote:


-----Original Message-----
From: Purkait, Soham <soham.purkait@intel.com>
Sent: 06 April 2026 10:27
To: Srinivas, Vidya <vidya.srinivas@intel.com>; igt-dev@lists.freedesktop.org;
Konieczny, Kamil <kamil.konieczny@intel.com>
Subject: Re: tools/gputop: Fix zero output when stdout is not a terminal

Hi Vidya,

On 02-04-2026 19:15, Vidya Srinivas wrote:

When gputop output is redirected to a file or pipe, such as:

   gputop -n 5 -d 1 > results.txt

Isn’t only stdout (fd 1) redirected to the file here?

I guess some thing like "echo test | ./gputop" would be returning the default
value (-1 in this case) for con_h.

Hello,

Many thanks for the review.
I will update the patch like this. Should be okay?

if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 &&
    ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1 &&
    ioctl(STDERR_FILENO, TIOCGWINSZ, &ws) == -1) {

I assume it's better to keep this : "if (ioctl(0, TIOCGWINSZ, &ws) == -1)" as is. As it won't make any  issue if the gputop output is redirected to any file or so (which only involve stdout).  The expression  will only be true when stdin is not a terminal, may be during running gputop in a ci.
And Its better to assign the default values to con_w and con_h in main. (please see below)

    ws.ws_col = 80;
    ws.ws_row = 50;
}

Regards
Vidya



        

          
   gputop -n 3 -d 2 | grep rcs

ioctl(0, TIOCGWINSZ) fails with -1 since stdin is not a terminal.
update_console_size() then returns without setting *w and *h, leaving
con_w and con_h at their initial value of -1.

The main display loop uses 'if (lines >= con_h) break' to limit output
to the terminal height. With con_h = -1, the condition (0 >= -1) is
immediately true on the very first line, causing all client output to
be silently suppressed. The result is that gputop produces only ANSI
clear- screen escape sequences and zero actual data.

This affects anyone using gputop in automation, CI pipelines, or any
non-interactive context on Linux or Android where output is redirected
or piped.

Fix this by falling back to a default console size of 80x50 when the
ioctl fails, consistent with the existing fallback for serial consoles
(where ws_col and ws_row are both 0).

Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
Reviewed-by: Kamil Konieczny <kamil.konieczny@linux.intel.com>
---
  tools/gputop.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/gputop.c b/tools/gputop.c index
9b2e8cb6f..112ec5ddb 100644
--- a/tools/gputop.c
+++ b/tools/gputop.c
@@ -505,8 +505,11 @@ static void update_console_size(int *w, int *h)
  {
  	struct winsize ws = {};

-	if (ioctl(0, TIOCGWINSZ, &ws) == -1)
+	if (ioctl(0, TIOCGWINSZ, &ws) == -1) {
+		*w = 80;
+		*h = 50;

        

      

    

    
 Imho instead of
      setting the values (*w = 80;*h = 50) here ,  it's better to initialize these as default values in main as "int con_w = 80, con_h = 50;" 

    
Thanks,
Soham

    

      

        

          

        

        
How about assigning the values during initialization in the main function ?

eg : int con_w = 80, con_h = 50;

Thanks,
Soham



        

          
  		return;
+	}

  	*w = ws.ws_col;
  	*h = ws.ws_row;


        

      

    

  


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