I'm rendering to a depth map in order to use it as a shader resource view, but when I sample the depth map in my shader, the red component has a value of 1 while all other channels have a value of 0.

The Texture2D I use to create the DepthStencilView is bound with the D3D11_BIND_DEPTH_STENCIL | D3D11_BIND_SHADER_RESOURCE flags, the DepthStencilView has the DXGI_FORMAT_D32_FLOAT format, and the ShaderResourceView's format is D3D11_SRV_DIMENSION_TEXTURE2D.

I'm setting the depth map render target, then i'm drawing my scene, and once that is done, I'm the back buffer render target and depth stencil are set on the output merger, and I'm using the depth map shader resource view as a texture in my shader, but the depth value in the red channel is constantly 1. I'm not getting any runtime errors from D3D, and no compile time warning or anything.

I'm not sure what I'm missing here at all. I have the impression the depth value is always being set to 1.

I have not set any depth/stencil states, and AFAICT depth writing is enabled by default. The geometry is being rendered correctly so I'm pretty sure depth writing is enabled.

The device is created with the appropriate debug flags;

#if defined(DEBUG) || defined(_DEBUG)
    deviceFlags |= D3D11_CREATE_DEVICE_DEBUG | D3D11_RLDO_DETAIL;
#endif

This is how I create my depth map. I've omitted error checking for the sake of brevity

D3D11_TEXTURE2D_DESC td;

td.Width     = width;
td.Height    = height;
td.MipLevels = 1;
td.ArraySize = 1;
td.Format    = DXGI_FORMAT_R32_TYPELESS;
td.SampleDesc.Count   = 1;  
td.SampleDesc.Quality = 0;  
td.Usage          = D3D11_USAGE_DEFAULT;
td.BindFlags      = D3D11_BIND_DEPTH_STENCIL | D3D11_BIND_SHADER_RESOURCE;
td.CPUAccessFlags = 0; 
td.MiscFlags      = 0;
_device->CreateTexture2D(&texDesc, 0, &this->_depthMap);

D3D11_DEPTH_STENCIL_VIEW_DESC dsvd;
ZeroMemory(&dsvd, sizeof(dsvd));
dsvd.Format = DXGI_FORMAT_D32_FLOAT;
dsvd.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
dsvd.Texture2D.MipSlice = 0;
_device->CreateDepthStencilView(this->_depthMap, &dsvd, &this->_dmapDSV);

D3D11_SHADER_RESOURCE_VIEW_DESC srvd;
srvd.Format = DXGI_FORMAT_R32_FLOAT;
srvd.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
srvd.Texture2D.MipLevels = texDesc.MipLevels;
srvd.Texture2D.MostDetailedMip = 0;
_device->CreateShaderResourceView(this->_depthMap, &srvd, &this->_dmapSRV);