diff --git a/Makefile.local b/Makefile.local
index 9ffca5c..91bc082 100644
--- a/Makefile.local
+++ b/Makefile.local
@@ -1,9 +1,16 @@
 
 check-mypy:
 	@echo "no op - swh-docs does not need typechecking, skipping"
 
 all:
 	@echo Building the whole documentation from source code repositories
 	@echo available in ../ via tox. This can take a while.
 	@echo Please be patient.
-	tox -r -e sphinx-dev
+	tox -vv -r -e sphinx-dev
+
+pip-install-swh-dev:
+	python3 -m pip install pifpaf
+	sed 's/#.*$$//;/^$$/d' requirements-swh-dev.txt | \
+	while IFS= read -r package; do \
+	  python3 -m pip install $$package ; \
+	done
diff --git a/tox.ini b/tox.ini
index 873aa12..b5cb988 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,41 +1,41 @@
 [tox]
 envlist=flake8,black
 
 [testenv]
 basepython = python3
 passenv = SPHINXOPTS JAVA_HOME
 
 [testenv:sphinx]
 extras =
   building
 deps =
   django < 3
   pifpaf
 setenv =
   SWHPKGDIR = {envsitepackagesdir}/swh
 commands =
   {envpython} -m pifpaf run postgresql -- make -C docs {posargs:html}
 
 [testenv:sphinx-dev]
-deps =
-  django < 3
-  -rrequirements-swh-dev.txt
-  pifpaf
+allowlist_externals = make
+# workaround really long dependencies installation due to the
+# new pip resolver and its backtracking processes
+install_command = make pip-install-swh-dev {packages}
 setenv =
   SWHPKGDIR = {envsitepackagesdir}/swh
 commands =
   {envpython} -m pifpaf run postgresql -- make -C docs {posargs:html}
 
 [testenv:black]
 skip_install = true
 deps =
   black==19.10b0
 commands =
   {envpython} -m black --check swh
 
 [testenv:flake8]
 skip_install = true
 deps =
   flake8
 commands =
   {envpython} -m flake8