Public bug reported:
Video is not working on the RaspberryPi3A+, and in dmesg there's this:
ubuntu@raspi3:~$ dmesg | grep cma
[ 0.000000] cma: Region at 0x10000000 defined on low/high memory boundary
(0x1c000000)
[ 0.000000] cma: Failed to reserve 256 MiB
[ 0.000000] Kernel command line: 8250.nr_uarts=1 cma=256M@256M
bcm2708_fb.fbwidth=1680 bcm2708_fb.fbheight=1050 bcm2708_fb.fbswap=1
dma.dmachans=0x7f35 bcm2709.boardrev=0x9020e0 bcm2709.serial=0x976d0cc5
bcm2709.uart_clock=48000000 bcm2709.disk_led_gpio=29
bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x1ec00000
vc_mem.mem_size=0x20000000 dwc_otg.lpm_enable=0 console=ttyS0,115200
console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
[ 0.000000] Memory: 438856K/458752K available (8816K kernel code, 550K
rwdata, 2688K rodata, 1024K init, 809K bss, 19896K reserved, 0K cma-reserved)
[ 1.209261] vc-cma: Videocore CMA driver
[ 1.213283] vc-cma: vc_cma_base = 0x00000000
[ 1.218091] vc-cma: vc_cma_size = 0x00000000 (0 MiB)
[ 1.223604] vc-cma: vc_cma_initial = 0x00000000 (0 MiB)
it tries to allocate 256M for CMA and fail, and that has a cascade
effect on the drm driver (that fails to init) and as such the video is
not working.
One easy workaround i found is to reduce the CMA size from 256M to 128M
on the bootargs:
[ 0.000000] cma: Reserved 128 MiB at 0x10000000
[ 0.000000] Kernel command line: 8250.nr_uarts=1 cma=128M@256M
bcm2708_fb.fbwidth=1680 bcm2708_fb.fbheight=1050 bcm2708_fb.fbswap=1
dma.dmachans=0x7f35 bcm2709.boardrev=0x9020e0 bcm2709.serial=0x976d0cc5
bcm2709.uart_clock=48000000 bcm2709.disk_led_gpio=29
bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x1ec00000
vc_mem.mem_size=0x20000000 dwc_otg.lpm_enable=0 console=ttyS0,115200
console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
[ 0.000000] Memory: 307528K/458752K available (8816K kernel code, 550K
rwdata, 2688K rodata, 1024K init, 809K bss, 20152K reserved, 131072K
cma-reserved)
[ 1.207110] vc-cma: Videocore CMA driver
[ 1.211131] vc-cma: vc_cma_base = 0x00000000
[ 1.215939] vc-cma: vc_cma_size = 0x00000000 (0 MiB)
[ 1.221454] vc-cma: vc_cma_initial = 0x00000000 (0 MiB)
this way the video works again.
** Affects: linux-raspi2 (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1805174
Title:
Xenial/raspi2 and RaspberryPi3A+: video not working
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