Re: [PATCH] drm/exynos: Add check for IOMMU while passing physically continous memory flag

[Rob Clark <robdclark@gmail.com>]

On Thu, Aug 1, 2013 at 7:20 PM, Tomasz Figa <tomasz.figa@gmail.com> wrote:
> Hi Vikas,
>
> On Thursday 01 of August 2013 16:49:32 Vikas Sajjan wrote:
>> While trying to get boot-logo up on exynos5420 SMDK which has eDP panel
>> connected with resolution 2560x1600, following error occured even with
>> IOMMU enabled:
>> [0.880000] [drm:lowlevel_buffer_allocate] *ERROR* failed to allocate
>> buffer. [0.890000] [drm] Initialized exynos 1.0.0 20110530 on minor 0
>>
>> This patch fixes the issue by adding a check for IOMMU.
>>
>> Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
>> Signed-off-by: Arun Kumar <arun.kk@samsung.com>
>> ---
>>  drivers/gpu/drm/exynos/exynos_drm_fbdev.c |    9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
>> b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c index 8e60bd6..2a86666
>> 100644
>> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
>> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
>> @@ -16,6 +16,7 @@
>>  #include <drm/drm_crtc.h>
>>  #include <drm/drm_fb_helper.h>
>>  #include <drm/drm_crtc_helper.h>
>> +#include <drm/exynos_drm.h>
>>
>>  #include "exynos_drm_drv.h"
>>  #include "exynos_drm_fb.h"
>> @@ -143,6 +144,7 @@ static int exynos_drm_fbdev_create(struct
>> drm_fb_helper *helper, struct platform_device *pdev = dev->platformdev;
>>       unsigned long size;
>>       int ret;
>> +     unsigned int flag;
>>
>>       DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d\n",
>>                       sizes->surface_width, sizes->surface_height,
>> @@ -166,7 +168,12 @@ static int exynos_drm_fbdev_create(struct
>> drm_fb_helper *helper, size = mode_cmd.pitches[0] * mode_cmd.height;
>>
>>       /* 0 means to allocate physically continuous memory */
>> -     exynos_gem_obj = exynos_drm_gem_create(dev, 0, size);
>> +     if (!is_drm_iommu_supported(dev))
>> +             flag = 0;
>> +     else
>> +             flag = EXYNOS_BO_NONCONTIG;
>
> While noncontig memory might be used for devices that support IOMMU, there
> should be no problem with using contig memory for them, so this seems more
> like masking the original problem rather than tracking it down.

it is probably a good idea to not require contig memory when it is not
needed for performance or functionality (and if it is only
performance, then fallback gracefully to non-contig).. but yeah, would
be good to know if this is masking another issue all the same

BR,
-R

> Could you check why the allocation fails when requesting contiguous
> memory?
>
> Best regards,
> Tomasz
>
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