Re: [PATCH 06/11] drm/radeon: stop using TTM_MEMTYPE_FLAG_MAPPABLE

From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: daniel@ffwll.ch
Cc: Madhav.Chauhan@amd.com, michael.j.ruhl@intel.com,
	tzimmermann@suse.de, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 06/11] drm/radeon: stop using TTM_MEMTYPE_FLAG_MAPPABLE
Date: Tue, 21 Jul 2020 16:46:18 +0200	[thread overview]
Message-ID: <8a602078-3dad-4158-6057-07427ea69d74@gmail.com> (raw)
In-Reply-To: <20200721092448.GE6419@phenom.ffwll.local>

Am 21.07.20 um 11:24 schrieb daniel@ffwll.ch:
> On Tue, Jul 21, 2020 at 09:32:40AM +0200, Christian König wrote:
>> The driver doesn't expose any not-mapable memory resources.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> ---
>>   drivers/gpu/drm/radeon/radeon_ttm.c | 13 ++++---------
>>   1 file changed, 4 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
>> index 54af06df865b..b474781a0920 100644
>> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
>> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
>> @@ -76,7 +76,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
>>   	switch (type) {
>>   	case TTM_PL_SYSTEM:
>>   		/* System memory */
>> -		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
>> +		man->flags = 0;
>>   		man->available_caching = TTM_PL_MASK_CACHING;
>>   		man->default_caching = TTM_PL_FLAG_CACHED;
>>   		break;
>> @@ -84,7 +84,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
>>   		man->func = &ttm_bo_manager_func;
>>   		man->available_caching = TTM_PL_MASK_CACHING;
>>   		man->default_caching = TTM_PL_FLAG_CACHED;
>> -		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
>> +		man->flags = 0;
>>   #if IS_ENABLED(CONFIG_AGP)
>>   		if (rdev->flags & RADEON_IS_AGP) {
>>   			if (!rdev->ddev->agp) {
>> @@ -92,8 +92,6 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
>>   					  (unsigned)type);
>>   				return -EINVAL;
>>   			}
>> -			if (!rdev->ddev->agp->cant_use_aperture)
>> -				man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
> There is a bunch of agp drivers (alpha, ppc, that kind of stuff) with this
> flag set. And radeon.ko did at least once work on these. And your patch to
> disable agp only changes the default, it doesn't rip out the code.

The key pint is that the flags for AGP are the same as the one for the 
PCIe path. So no functional change at all :)

The real handling of cant_use_aperture is in radeon_ttm_io_mem_reserve().

Christian.

>
> So not sure your assumption here is correct.
> -Daniel
>
>>   			man->available_caching = TTM_PL_FLAG_UNCACHED |
>>   						 TTM_PL_FLAG_WC;
>>   			man->default_caching = TTM_PL_FLAG_WC;
>> @@ -103,8 +101,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
>>   	case TTM_PL_VRAM:
>>   		/* "On-card" video ram */
>>   		man->func = &ttm_bo_manager_func;
>> -		man->flags = TTM_MEMTYPE_FLAG_FIXED |
>> -			     TTM_MEMTYPE_FLAG_MAPPABLE;
>> +		man->flags = TTM_MEMTYPE_FLAG_FIXED;
>>   		man->available_caching = TTM_PL_FLAG_UNCACHED | TTM_PL_FLAG_WC;
>>   		man->default_caching = TTM_PL_FLAG_WC;
>>   		break;
>> @@ -394,7 +391,6 @@ static int radeon_bo_move(struct ttm_buffer_object *bo, bool evict,
>>   
>>   static int radeon_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
>>   {
>> -	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
>>   	struct radeon_device *rdev = radeon_get_rdev(bdev);
>>   
>>   	mem->bus.addr = NULL;
>> @@ -402,8 +398,7 @@ static int radeon_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_
>>   	mem->bus.size = mem->num_pages << PAGE_SHIFT;
>>   	mem->bus.base = 0;
>>   	mem->bus.is_iomem = false;
>> -	if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
>> -		return -EINVAL;
>> +
>>   	switch (mem->mem_type) {
>>   	case TTM_PL_SYSTEM:
>>   		/* system memory */
>> -- 
>> 2.17.1
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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