Vysor (FrameBuffer clone) support on Linaro kernel 4.14?

Hi,

I’m trying to get Vysor working with Linaro kernel 4.14/AOSP on a Dragonboard 410c.(https://www.vysor.io/download/?return=https%3A%2F%2Fwww.vysor.io%2F)

With the clean image of Linaro snapshots 283, the HDMi output is working and the /dev/graphics/fb0 is installed. However, I can’t see the cloned display in Vysor. In fact, when I tried to perform “cat /dev/graphics/fb0”, there is nothing output.

Any ideas? More than happy to provide more details if required!

Thank you for your time !
Ian

On DB410C rendering is performed via DRM interface, not fbdev, there is however indeed a wrapper exposing a legacy fbdev.

Try cat dev/fb0 > fbdump.raw it generates right sized file on my side (I’m using debian).

Hi Loic

Thanks for the information.
On my side, all data content is 0x00 even using cat /dev/graphics/fb0 > fbdump.raw

Besides, there is no /dev/fb* device being registered in the system.
Should I enable more configurations in db410c-qcomlt-4.14_defconfig? In default, only the below DRM config are enabled.

CONFIG_DRM=y
CONFIG_DRM_I2C_ADV7511=y
CONFIG_DRM_I2C_ADV7511_AUDIO=y

Could you please let me know how to enable the legacy fbdev?
In fact, I had modified the db410c-qcomlt-4.14_defconfig into following configuration. But, there is still no /dev/fb* node being created.

CONFIG_DRM=y
CONFIG_DRM_I2C_ADV7511=y
CONFIG_DRM_I2C_ADV7511_AUDIO=y
CONFIG_DRM_KMS_HELPER=y
CONFIG_DRM_KMS_FB_HELPER=y
CONFIG_DRM_FBDEV_EMULATION=y

Thanks and Regards,
Ian