diff --git a/curl.spec b/curl.spec
index 4b0a408..26637bd 100644
--- a/curl.spec
+++ b/curl.spec
@@ -52,7 +52,12 @@ BuildRequires: perl(Time::HiRes)
 BuildRequires: perl(warnings)
 BuildRequires: perl(vars)
 
-# require valgrind to boost test coverage on i386 and x86_64
+# The test-suite runs automatically trough valgrind if valgrind is available
+# on the system.  By not installing valgrind into mock's chroot, we disable
+# this feature for production builds on architectures where valgrind is known
+# to be less reliable, in order to avoid unnecessary build failures (see RHBZ
+# #810992, #816175, and #886891).  Nevertheless developers are free to install
+# valgrind manually to improve test coverage on any architecture.
 %ifarch %{ix86} x86_64
 BuildRequires: valgrind
 %endif