Re: [igt-dev] [PATCH i-g-t 2/8] tests/i915/gem_exec_capture: Cope with larger page sizes

[Matthew Brost <matthew.brost@intel.com>]

On Fri, Oct 29, 2021 at 05:32:40PM -0700, John Harrison wrote:
> On 10/29/2021 10:39, Matthew Brost wrote:
> > On Thu, Oct 21, 2021 at 04:40:38PM -0700, John.C.Harrison@Intel.com wrote:
> > > From: John Harrison <John.C.Harrison@Intel.com>
> > > 
> > > At some point, larger than 4KB page sizes were added to the i915
> > > driver. This included adding an informational line to the buffer
> > > entries in error capture logs. However, the error capture test was not
> > > updated to skip this string, thus it would silently abort processing.
> > > 
> > > Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> > > ---
> > >   tests/i915/gem_exec_capture.c | 6 ++++++
> > >   1 file changed, 6 insertions(+)
> > > 
> > > diff --git a/tests/i915/gem_exec_capture.c b/tests/i915/gem_exec_capture.c
> > > index 53649cdb2..47ca64dd6 100644
> > > --- a/tests/i915/gem_exec_capture.c
> > > +++ b/tests/i915/gem_exec_capture.c
> > > @@ -484,6 +484,12 @@ static void many(int fd, int dir, uint64_t size, unsigned int flags)
> > >   		addr |= strtoul(str + 1, &str, 16);
> > >   		igt_assert(*str++ == '\n');
> > > +		/* gtt_page_sizes = 0x00010000 */
> > > +		if (strncmp(str, "gtt_page_sizes = 0x", 19) == 0) {
> > > +			str += 19 + 8;
> > > +			igt_assert(*str++ == '\n');
> > > +		}
> > Can you explain this logic to me, for the life of me I can't figure out
> > what this doing. That probably warrent's a more detailed comment too.
> It's no different to the rest of the processing that this code was already
> doing.
> 
> if( start_of_current_line == "gtt_page_sizes = 0x") {
>     current_line += strlen(above_string) + strlen(8-digit hex string);
>     assert( next_character_of_current_line == end_of_line);
> }
> 
> I.e. skip over any line that just contains the page size message.
> 

Ok, got it. Not sure I missed that. The magic numbers 19 and 8 where
confusing me but I understand this now.

With that:
Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> John.
> 
> > 
> > Matt
> > 
> > > +
> > >   		if (!(*str == ':' || *str == '~'))
> > >   			continue;
> > > -- 
> > > 2.25.1
> > > 
>