[PATCH v2] drm/exynos: gem: Drop NONCONTIG flag for buffers allocated without IOMMU

[Tobias Jakobi]

Inki Dae wrote:
> 
> 
> 2017년 11월 22일 22:14에 Marek Szyprowski 이(가) 쓴 글:
>> When no IOMMU is available, all GEM buffers allocated by Exynos DRM driver
>> are contiguous, because of the underlying dma_alloc_attrs() function
>> provides only such buffers. In such case it makes no sense to keep
>> BO_NONCONTIG flag for the allocated GEM buffers. This allows to avoid
>> failures for buffer contiguity checks in the subsequent operations on GEM
>> objects.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
>> CC: stable at vger.kernel.org # v4.4+
>> ---
>> This issue is there since commit 0519f9a12d011 ("drm/exynos: add iommu
>> support for exynos drm framework"), but this patch applies cleanly
>> only to v4.4+ kernel releases due changes in the surrounding code.
>>
>> Changelog:
>> v2:
>> - added warning message when buffer flags are updadated (requested by Inki)
>>
>> v1: https://patchwork.kernel.org/patch/10034919/
>> - initial version
>> ---
>>  drivers/gpu/drm/exynos/exynos_drm_gem.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
>> index 077de014d610..4400efe3974a 100644
>> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
>> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
>> @@ -247,6 +247,15 @@ struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
>>  	if (IS_ERR(exynos_gem))
>>  		return exynos_gem;
>>  
>> +	if (!is_drm_iommu_supported(dev) && (flags & EXYNOS_BO_NONCONTIG)) {
>> +		/*
>> +		 * when no IOMMU is available, all allocated buffers are
>> +		 * contiguous anyway, so drop EXYNOS_BO_NONCONTIG flag
>> +		 */
>> +		flags &= ~EXYNOS_BO_NONCONTIG;
>> +		DRM_WARN("Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer\n");
> 
> WARNING: line over 80 characters
That warning is bogus. Message strings are not supposed to be split.


> I wil change above a warning like below if you are ok,
> 	DRM_WARN("Changed to CONTIG buffer due to no IOMMU support.\n");
I think Marek's message is more descriptive.

- Tobias

> 
> 
> Thanks,
> Inki Dae
> 
>> +	}
>> +
>>  	/* set memory type and cache attribute from user side. */
>>  	exynos_gem->flags = flags;
>>  
>>
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