Source: rtl-sdr Version: 2.0.3-1 Severity: normal Tags: patch Dear Maintainer,
the fix for #1041701 (2.0.1-2) is ineffective. Line 13 of debian/rules reads "-DENABLE_ZEROCOPY=$DEB_ZEROCOPY_OPTION", which make expands as $D followed by the literal text "EB_ZEROCOPY_OPTION". CMake therefore receives -DENABLE_ZEROCOPY=EB_ZEROCOPY_OPTION, which is truthy, so zero-copy is enabled on all architectures, including ARM. The arm64 buildd log for 2.0.3-1 confirms this: "Building with usbfs zero-copy support enabled". Impact: on SoCs with non-coherent USB DMA (e.g. RK3588, Raspberry Pi) the mmapped usbfs buffers are uncached. With dumpvdl2 on an RK3588 (trixie, librtlsdr0 2.0.2-2+b1) the thread reading the buffers uses about 52% of a core, versus about 2.6% when the buffer is copied first. The attached patch changes it to $(DEB_ZEROCOPY_OPTION). Checked with "make -n -f debian/rules override_dh_auto_configure": DEB_BUILD_ARCH=arm64 now gives OFF, amd64 gives ON. Possibly DEB_HOST_ARCH instead of DEB_BUILD_ARCH in line 6 would be more correct for cross builds. Regards, Martin Paul
diff --git a/debian/rules b/debian/rules index fe75936..436781a 100755 --- a/debian/rules +++ b/debian/rules @@ -10,7 +10,7 @@ DEB_ZEROCOPY_OPTION=$(shell if [ $(DEB_BUILD_ARCH) = arm64 ] || [ $(DEB_BUILD_AR override_dh_auto_configure: debian/librtlsdr0.udev dh_auto_configure --buildsystem=cmake -- -DDETACH_KERNEL_DRIVER=ON \ - -DENABLE_ZEROCOPY=$DEB_ZEROCOPY_OPTION \ + -DENABLE_ZEROCOPY=$(DEB_ZEROCOPY_OPTION) \ -DINSTALL_UDEV_RULES=ON \ -DCMAKE_BUILD_TYPE=RelWithDebInfo \ -DCMAKE_VERBOSE_MAKEFILE=ON
