Import Debian changes 1.20210303+ds-2

debian/changelog

+raspi-firmware (1.20210303+ds-2) unstable; urgency=medium
+
+  * Add a header to config.txt warning users it's an autogenerated file
+    (Closes: #983896)
+  * Added config option GPU_FREQ to allow specifying a fixed GPU speed,
+    needed for using the serial console in the RPi4 family
+  * ignore *.old-dkms when configuring a new kernel/initrd (Closes:
+    #983409)
+  * Applied some shellcheck fixes to improve clarity. Thanks Diederik!
+
+ -- Gunnar Wolf <gwolf@debian.org>  Wed, 21 Apr 2021 00:52:21 -0500
+
 raspi-firmware (1.20210303+ds-1) unstable; urgency=medium
 
   * New upstream release

debian/default/raspi-firmware

@@ -67,6 +67,25 @@
 #
 #CONSOLES="auto"
 
+# In the RPi4 and p400 families, the video processor (GPU) has several
+# possible operating frequencies, but is known to corrupt the serial
+# console (switch to an invalid baud rate), as the UART (the component
+# which drives the serial ports) gets its clock from the GPU, as
+# explained here:
+#
+# https://www.raspberrypi.org/documentation/configuration/uart.md
+#
+# The clock speeds the RPi4 GPU uses are 360/500/550 MHz. If you
+# intend to use the serial console, you need to set GPU_FREQ to
+# 360. If you intend to use this computer as a desktop system, set it
+# to "auto". Both 500 and 550 MHz also corrupt the serial console.
+#
+# Do note that earlier models have fixed frequencies, and this setting
+# will be ignored if your board does not identify as a RPi 4 (any
+# model) or p400.
+#
+#GPU_FREQ="auto"
+
 # Force the architecture to install the kernel as. You will most
 # likely want to leave this setting alone; the only use case I have
 # found for this is when you want to run a 32-bit userland on a

debian/kernel/postinst.d/z50-raspi-firmware

 #!/bin/sh
 # vim:ts=2:sw=2:et
 # see also:
-# https://kernel-handbook.alioth.debian.org/ch-update-hooks.html#s-kernel-hooks
+# https://kernel-team.pages.debian.net/kernel-handbook/ch-update-hooks.html#s-kernel-hooks
 
 set -e
 
@@ -31,13 +31,15 @@ fi
 # Ensure the target directory exists. See https://bugs.debian.org/887062
 mkdir -p /boot/firmware
 
-latest_kernel=$(ls -1 /boot/vmlinuz-* | grep -v '\.dpkg-bak$' | sort -V -r | head -1)
+# shellcheck disable=SC2010
+latest_kernel=$(ls -1 /boot/vmlinuz-* | grep -E -v '\.(dpkg-bak|old-dkms)$' | sort -V -r | head -1)
 if [ -z "$latest_kernel" ]; then
   echo "raspi-firmware: no kernel found in /boot/vmlinuz-*, cannot populate /boot/firmware"
   exit 0
 fi
 
-latest_initrd=$(ls -1 /boot/initrd.img-* | grep -v '\.dpkg-bak$' | sort -V -r | head -1)
+# shellcheck disable=SC2010
+latest_initrd=$(ls -1 /boot/initrd.img-* | grep -E -v '\.(dpkg-bak|old-dkms)$' | sort -V -r | head -1)
 if [ -z "$latest_initrd" ]; then
   echo "raspi-firmware: no initrd found in /boot/initrd.img-*, cannot populate /boot/firmware"
   exit 0
@@ -76,7 +78,7 @@ else
 fi
 
 if [ "$KERNEL" = "auto" ]; then
-  for dtb in ${dtb_path}/bcm*.dtb; do
+  for dtb in "${dtb_path}"/bcm*.dtb; do
       [ -e "${dtb}" ] || continue
       cp "${dtb}" /boot/firmware/
   done
@@ -92,7 +94,17 @@ fi
 
 
 # Truncate the config.txt file so that we start with a blank slate
-: >/boot/firmware/config.txt
+echo <<EOF >/boot/firmware/config.txt
+# Do not modify this file!
+#
+# It is automatically generated upon install or update of either the
+# firmware or the Linux kernel.
+#
+# If you need to set boot-time parameters, do so via the
+# /etc/default/raspi-firmware or /etc/default/raspi-extra-cmdline
+#files.
+
+EOF
 
 if [ "$arch" = "arm64" ]; then
   cat >/boot/firmware/config.txt <<EOF
@@ -102,6 +114,16 @@ arm_64bit=1
 EOF
 fi
 
+if grep -q 'Raspberry Pi 4' /sys/firmware/devicetree/base/model
+then
+    # This matches all RPi4 boards ("Raspberry Pi 4 Model B Rev 1.4")
+    # and p400 full computer systems ("Raspberry Pi 400 Rev 1.0")
+    if [ "$GPU_FREQ" != "auto" ]
+    then
+	echo "core_freq=$GPU_FREQ" >> /boot/firmware/config.txt
+    fi
+fi
+
 cat >>/boot/firmware/config.txt <<EOF
 enable_uart=1
 upstream_kernel=1
@@ -122,7 +144,7 @@ if [ -f "$firmware_custom" ]; then
   cat >>/boot/firmware/config.txt <<EOF
 
 # Inserted by ${firmware_custom}
-`cat ${firmware_custom}`
+$(cat ${firmware_custom})
 EOF
 fi
 
@@ -164,7 +186,7 @@ fi
 
 cmdline_custom="/etc/default/raspi-extra-cmdline"
 if [ -f "$cmdline_custom" ]; then
-    post_cmdline=`cat $cmdline_custom`
+  post_cmdline=$(cat $cmdline_custom)
 fi
 
 cat >/boot/firmware/cmdline.txt <<EOF