I have a Raspberry Pi 3 running Raspbian Jessie with a PiTFT 2.8" resistive screen. Everything is working great, except that the resolution is not optimal; icons and text are too big for the screen to be 100% useful.

I tried different things, so far nothing worked.

First thing I tried was to change resolution related parameters in /boot/config.txt:

# uncomment to force a console size. By default it will be display's size minus
# overscan.

With no effect. I tried another strategy, still playing with /boot/config.txt, following what I read here:

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_cvt=320 240 60 1 0 0 0

With no effect. I changed strategy again, following some leads on the Xorg side. First, I saw what I could do with xrandr:

~$ DISPLAY=:0 xrandr --dpi 60

That returns an error:

xrandr: Failed to get size of gamma for output default

I read somewhere else that one could also change it through startx:

FRAMEBUFFER=/dev/fb1 sudo startx -- -dpi 30

With no effect (X restart, but everything stays the same). I then tried to modify some things in Xorg configuration (following this lead), adding to /etc/X11/xorg/conf.d/99-calibration.conf the following lines:

Section "Monitor"
        Identifier      "<default monitor>"
        DisplaySize 85 64
        Option "DPI" "60 x 60"

I got the parameters from xdpyinfo.

Reboot. No effect.

I'm out of ideas (so does my favorite search engines). Any hints would be greatly appreciated!

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