Re: [igt-dev] [PATCH i-g-t 1/3 v5] lib/igt_kms: Fix memory corruption

["Modem, Bhanuprakash" <bhanuprakash.modem@intel.com>]

On Fri-10-11-2023 05:08 pm, Vignesh Raman wrote:
> Hi Bhanu,
> 
> On 10/11/23 15:21, Modem, Bhanuprakash wrote:
>>> @@ -2770,6 +2770,10 @@ void igt_display_require(igt_display_t 
>>> *display, int drm_fd)
>>>       }
>>>   #endif
>>> +    igt_require_f(resources->count_crtcs <= IGT_MAX_PIPES,
>> ---------------------------------------------^
>> As pipe index starts from 0, we must use '<' not '<='.
> 
> igt_require_f - Skip a (sub-)test if a condition is not met
> 
> igt_require_f(resources->count_crtcs <= IGT_MAX_PIPES,
>                       "count_crtcs exceeds IGT_MAX_PIPES, 
> resources->count_crtcs=%d, IGT_MAX_PIPES=%d\n",
>                       resources->count_crtcs, IGT_MAX_PIPES);
> 
> If count_crtcs=16 and IGT_MAX_PIPES=16 (In the current case with 
> virtio-gpu),
> 
> count_crtcs <= IGT_MAX_PIPES will be true and test requirement is passed 
> and following statement will be executed.
> display->n_pipes = IGT_MAX_PIPES;
> 
> In another case,
> count_crtcs < IGT_MAX_PIPES will be false and test will be skipped,
> 
> So we need to use <= right?

Correct, please ignore my previous comment. Thanks for the clarification.

- Bhanu

> 
>>>   enum pipe {
>>> @@ -70,7 +80,15 @@ enum pipe {
>>>           PIPE_F,
>>>       PIPE_G,
>>>       PIPE_H,
>>> -        IGT_MAX_PIPES
>>> +    PIPE_I,
>>> +    PIPE_J,
>>> +    PIPE_K,
>>> +    PIPE_L,
>>> +    PIPE_M,
>>> +    PIPE_N,
>>> +    PIPE_O,
>>> +    PIPE_P,
>>> +    IGT_MAX_PIPES
>>
>> Please don't mix tabs & spaces, and try to align with the declaration 
>> of previous pipes.
> 
> The previous ones G and H used tabs and the rest were spaces. I will use 
> spaces for all now.
> 
>>
>> Apart from these minor fixes, this patch LGTM. With above comments 
>> addressed, this patch is
>>
>> Reviewed-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
> 
> Thank you.
> 
> Regards,
> Vignesh