I would be surprised if the size argument was the issue. That comes right out out of the create IOCTL unmodified. Here is the full source that I am using.
// Clear the arg buffers.
memset(&create_arg, 0, sizeof(create_arg));
memset(&map_arg, 0, sizeof(map_arg));
// ------------------------------------------------------------------------
// Allocate
// Fill in the arguments for the IOCTL. Note that we only support 32bpp
// dumb buffers so that is hard coded here.
create_arg.width = width;
create_arg.height = height;
create_arg.bpp = 32;
// Allocate the dumb buffer
if (drmIoctl(gpu->fd(), DRM_IOCTL_MODE_CREATE_DUMB, &create_arg))
{
svWarning(0) << "Failed: DRM_IOCTL_MODE_CREATE_DUMB - " << strerror(errno);
return;
}
// Store the dumb buffer properties.
mSize = create_arg.size;
mStride = create_arg.pitch;
mHandle = create_arg.handle;
// ------------------------------------------------------------------------
// Map
// Fill in the arguments for the IOCTL.
map_arg.handle = mHandle;
// Allocate the dumb buffer
if (drmIoctl(gpu->fd(), DRM_IOCTL_MODE_MAP_DUMB, &map_arg))
{
svWarning(0) << "Failed: DRM_IOCTL_MODE_MAP_DUMB - " << strerror(errno);
return;
}
// Store the mapped memory
if ((mVaddr = (svuint32 *)mmap(0, mSize, PROT_READ | PROT_WRITE, MAP_SHARED, gpu->fd(), map_arg.offset)) == MAP_FAILED)
{
// Need to clear out the address so that we don't try to use it.
mVaddr = NULL;
// Error out.
svWarning(0) << "Failed: Dumb Buffer mmap - " << strerror(errno);
return;
}
When this code runs, I get the "Invalid Argument" on the mmap.
On Mon, Nov 10, 2014 at 4:14 PM, Dave Airlie <airlied@xxxxxxxxx> wrote:
On 11 November 2014 06:33, Rian Quinn <rianquinn@xxxxxxxxx> wrote:
> I did another test using the following that David put up on github:
>
> https://github.com/dvdhrm/docs/blob/master/drm-howto/modeset.c
>
> This test also fails on everything except Intel. What's really strange is
> this test actually does a test to verify that dumb buffers are supported,
> and the test passes in all cases. David's code is returning with the same
> error of "Invalid Argument" on the mmap call. Why would the other driver's
> claim to support dumb buffers, but have no means to map the memory?
Just a guess, the size argument is wrong.
But you know you have the kernel source, stick some printks in the
EINVAL return paths already.
Dave.
> - Rian
>
> On Mon, Nov 10, 2014 at 2:48 PM, Rian Quinn <rianquinn@xxxxxxxxx> wrote:
>>
>> When working with dumb buffers, DRM_IOCTL_MODE_MAP_DUMB and mmap works
>> fine on Intel, but the mmap call fails on Radeon, Nouveau, and VMWGFX. I you
>> look at the source for the xorg moderating driver, it only uses the dumb
>> buffer IOCTL (i.e. it’s not using LibKMS), and if you look at the kernel
>> source code for the dumb buffer IOCTLs for each of the Radeon, Nouveau, and
>> VMWGFX drivers, they all implement the functions. Furthermore all of the
>> IOCTLs succeed without error. Its only when you attempt to map the memory,
>> that you get an error of “Invalid Argument”. Here is my map call:
>>
>> mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, map_arg.offset)
>>
>> Is this a bug, or is there a different way to map the dumb buffers for
>> these drivers other than LibKMS.
>>
>> Thanks,
>> - Rian
>
>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
_______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
