[Intel-gfx] [PATCH 1/2] drm/i915/gtt: Fix pte clear range

[Mika Kuoppala]

Joonas Lahtinen <joonas.lahtinen at linux.intel.com> writes:

> On ma, 2016-10-31 at 17:55 +0200, Mika Kuoppala wrote:
>> @@ -712,13 +712,13 @@ static int gen8_48b_mm_switch(struct i915_hw_ppgtt *ppgtt,
>>   */
>>  static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm,
>>  				struct i915_page_table *pt,
>> -				uint64_t start,
>> -				uint64_t length)
>> +				const uint64_t start,
>> +				const uint64_t length)
>>  {
>
> I think const for integers is bit much, with that logic we should make
> the pointers const too (not the pointer destination).
>

It is more of a compiler guard of accidentally changing these
in the body. Separation of variants and invariants. But
if this not preferred, I can change them back.

>> @@ -735,8 +737,8 @@ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm,
>>  
>>  	pt_vaddr = kmap_px(pt);
>>  
>> -	for (pte = pte_start; pte < num_entries; pte++)
>> -		pt_vaddr[pte] = scratch_pte;
>> +	while (pte < pte_end)
>> +		pt_vaddr[pte++] = scratch_pte;
>
> I'd prefer the for loop still. Just fix "pte < pte_end".
>

I changed to this due to pte being already set and
used before the loop, to get rid of superfluous pte_start.
-Mika


> Regards, Joonas
> -- 
> Joonas Lahtinen
> Open Source Technology Center
> Intel Corporation