How to change Saints Row 4 aspect ratio from portrait to landscape?

I just started Saints Row IV for the first time, and it's wrongly chosen an aspect ratio of 10:16. That sometimes happens because I've got one vertical and one horizontal screen. In most games I just change it in the options, however:

It looks like the main menu has been scaled for a screen size of 3072x1920 (16:10) and then cropped to the right-most 1200x1920, so most of it is unreadable:
When I managed to get to the display menu (third from the bottom on the main menu, then second from the bottom), it says something at the bottom that looks like "Aspect ratio can only be toggled in the title screen". Once I get to the title screen, how do I do that? I tried setting the resolution in ~/.local/share/Steam/SteamApps/common/Saints Row IV/display.ini, but the game seems to ignore those changes.

pc linux saints-row-iv

Best Answer

After fiddling with the game settings several times it eventually stuck. Here's the configuration diff if anyone else might be helped by it:

$ diff ~/.local/share/Steam/SteamApps/common/Saints\ Row\ IV/display.ini{.orig,}
5,9c5,9
< ResolutionWidth = 1200
< ResolutionHeight = 1920
< RefreshRate = 59
< MSAA_Level = 2
< Fullscreen = true
---
> ResolutionWidth = 1920
> ResolutionHeight = 1200
> RefreshRate = 60
> MSAA_Level = 1
> Fullscreen = false
24c24
< VSync = false
---
> VSync = true
28c28
< Preset = 2
---
> Preset = 4
34c34
< AnisoLevel = 2
---
> AnisoLevel = 16
37c37
< LightingDetail = 1
---
> LightingDetail = 2
40c40
< SSAO_Level = 1
---
> SSAO_Level = 3
45c45
< ShadowDetail = 1024
---
> ShadowDetail = 4096
49c49
< SceneDetail = 2
---
> SceneDetail = 3
52c52
< Reflections = 1
---
> Reflections = 2
62c62
< PostProcess = 1
---
> PostProcess = 2