please include vc4 modules in pi2-kernel snap initrd

[Oliver Grawert]

Impact:

when using the vc4-kms-v3d devicetree overlay to get accelerated graphics /dev/fb0 is handled by the vc4 driver.

since this module does not exist in the initrd currently, using the framebuffer for something like an early splash screen from the initrd is impossible (it works fine when using the vc4-fkms-v3d overlay which hands framebuffer handling back over to the kernel instead, but this sadly results in a completely unaccelerated graphics stack)

the list of modules to include is:

drm_kms_helper.ko
drm.ko
drm_mipi_dsi.ko
vc4.ko
sysimgblt.ko
sysfillrect.ko
syscopyarea.ko
fb_sys_fops.ko
i2c-bcm2708.ko

Fix:

add the i2c-bcm2708.ko to initrd

How to test:

generate the pi2-kernep snap after applying the below patch, unsquash it, and checks that initrd.img contains all the above kmods (see #2).

Regression:

None, it's a trivial one-line change.

[Oliver Grawert (ogra)]

note that alternatively compiling vc4 into the kernel would perhaps work too, but i guess people with headless use-cases that want to save on RAM would find this disturbing.

[Paolo Pisati (p-pisati)]

Actually, of the above list, all but one kmod are already included in the initramfs:

lib/modules/4.4.0-1098-raspi2/kernel/drivers/gpu/drm/drm_kms_helper.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/gpu/drm/drm.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/gpu/drm/drm_mipi_dsi.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/gpu/drm/vc4/vc4.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/video/fbdev/core/sysimgblt.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/video/fbdev/core/sysfillrect.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/video/fbdev/core/syscopyarea.ko
lib/modules/4.4.0-1098-raspi2/kernel/drivers/video/fbdev/core/fb_sys_fops.ko

The patch attached changes the pi2-kernel snap creation script and adds the i2c-bcm2709 kmod to initrd:

--- pi2-kernel_4.4.0-1098/initrd.log 2018-09-27 13:01:19.393419321 +0200
+++ pi2-kernel_4.4.0-1098-lp1794279/initrd.log 2018-09-27 11:57:56.444606049 +0200
@@ -259,6 +259,9 @@
 lib/modules/4.4.0-1098-raspi2/kernel/drivers/virtio
 lib/modules/4.4.0-1098-raspi2/kernel/drivers/virtio/virtio_ring.ko
 lib/modules/4.4.0-1098-raspi2/kernel/drivers/virtio/virtio.ko
+lib/modules/4.4.0-1098-raspi2/kernel/drivers/i2c
+lib/modules/4.4.0-1098-raspi2/kernel/drivers/i2c/busses
+lib/modules/4.4.0-1098-raspi2/kernel/drivers/i2c/busses/i2c-bcm2708.ko
 lib/modules/4.4.0-1098-raspi2/kernel/drivers/video
 lib/modules/4.4.0-1098-raspi2/kernel/drivers/video/fbdev
 lib/modules/4.4.0-1098-raspi2/kernel/drivers/video/fbdev/cor

[Paolo Pisati (p-pisati)]

And here is a pi2 kernel snap with the above modification applied, can you test it?

[Oliver Grawert (ogra)]

works perfect !!!