Re-purpose remote-enabled EEPROM flag to determine if direct sampling mode should be forced ON. Useful for apps that don't have any direct sampling mode settings in their GUI.
Re-purpose remote-enabled EEPROM flag to determine if direct sampling mode should be forced ON. Useful for apps that don't have any direct sampling mode settings in their GUI.
Use the offset tuning button to enable the bias tee on the V3. Offset tuning is not used for the R820T so this is okay and allows us to toggle the bias tee on software that hasn't implemented specific bias tee controls.
Although we added a detection mechanism for the presence of the Kernel
bug earlier, reading from the incorrectly mapped memory might cause a
bus error on some ARM systems.
With the overall performance benefit being rather minimal for the
data rates of rtl-sdr, disable zero-copy by default.
Removed the linked list structure, locking, and malloc/free on each USB callback.
Replaced it with a non blocking ring buffer for performance. This resulted
in a large performance improvement when using an Raspberry Pi or Raspberry Pi Zero W
as a rtl_tcp server. The sample rate could be doubled and instead of wired ethernet
wifi could be used. Frequnecy change lag was reduced greatly also.
Signed-off-by: Stephen Blinick <stephen@stesoft.com>
The Linux Kernel has a bug on ARM/ARM64 systems where the USB CMA
memory is incorrectly mapped to userspace, breaking zerocopy.
When the Kernel allocates the memory, it clears it with memset().
If the mapping worked correctly, we should have zeroed out buffers,
if it doesn't, we get random Kernel memory. We now check for this,
and fall back to buffers in userspace if that's the case.
Signed-off-by: Steve Markgraf <steve@steve-m.de>
With just 'inline', if the compiler decides not to inline them, it isn't
required to emit them at all. For some targets with -Os that is causing
build failures, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86360.
Perhaps we might consider using '__attribute__((always_inline))' for
GCC builds, but 'static inline' is a good start.
Signed-off-by: Steve Markgraf <steve@steve-m.de>
