minor things

README.md

@@ -28,6 +28,13 @@ Libraries:
 
 Note that you can put `using MKL` into your `startup.jl` to make Julia automatically use Intel MKL in every session.
 
+To switch back to "using OpenBLAS" in an active session, you can run the following code
+
+```julia
+using OpenBLAS_jll
+LinearAlgebra.BLAS.lbt_forward(OpenBLAS_jll.libopenblas_path; clear=true);
+```
+
 ### Using a preinstalled Intel MKL
 
 If you already have an Intel MKL installation available (as on most HPC clusters), you can use the the environment variable `JULIA_MKL_PATH` or the [preference](https://github.com/JuliaPackaging/Preferences.jl) `mkl_path` to hint MKL.jl to the `libmkl_rt` library. Specifically, the options are:
@@ -38,7 +45,6 @@ If you already have an Intel MKL installation available (as on most HPC clusters
 
 Note that, in contrast to the preference, the environment variable only has an effect when MKL.jl is (re-)precompiled. To force a change of the MKL path after the compilation has happened, use the function `MKL.set_mkl_path`, which takes the options listed above as input.
 
-
 ## Installation (Julia 1.6 and older)
 
 On older releases of Julia, a new system image build happens right after installation. If it doesn't (happens when MKL_jll.jl has been installed before), run the following command to build a new system image and restart Julia.
@@ -55,7 +61,7 @@ julia> BLAS.vendor() # replaced by BLAS.get_config() in Julia versions >= 1.7
 :mkl
 ```
 
-To revert back to OpenBLAS you currently need to reinstall Julia.
+For Julia 1.6 and older, you need to reinstall Julia to revert back to using OpenBLAS.
 
 ## 64-bit vs 32-bit version of Intel MKL
 

src/MKL.jl

@@ -2,6 +2,7 @@ module MKL
 
 using Preferences
 using Libdl
+using LinearAlgebra
 
 # Choose an MKL provider/path; taking an explicit preference as the first choice,
 # but if nothing is set as a preference, fall back to an environment variable,
@@ -42,8 +43,6 @@ end
 
 is_lbt_available() = VERSION > v"1.7.0-DEV.641"
 
-is_lbt_available() && using LinearAlgebra
-
 if Base.USE_BLAS64
     const MKLBlasInt = Int64
 else

test/runtests.jl

@@ -3,7 +3,7 @@ using MKL
 using Test
 
 if MKL.is_lbt_available()
-    @test BLAS.get_config().loaded_libs[1].libname == libmkl_rt
+    @test BLAS.get_config().loaded_libs[1].libname == MKL.libmkl_rt
 else
     @test BLAS.vendor() == :mkl
 end