How to configure a desired screen resolution

[Kevin Oberman]

On Wed, Oct 15, 2014 at 10:50 PM, Jin Guojun <jguojun at sbcglobal.net> wrote:
> I am not sure why you think this is BIOS issue. If this is BIOS issue, only
> one monitor should work with ASUS motherboard according to your theory.
>
> Monitor A works on medium resolution, and Monitor B works on higher
> resolution but not works in the medium resolution individually.
> However, when both Monitors are attached to the ASUS motherboard, then both
> can work in the medium resolution. From this point, neither the BIOS nor the
> Monitor is the issue.
>
>
>
> On Wednesday, October 15, 2014 6:11 PM, Kevin Oberman <rkoberman at gmail.com>
> wrote:
>
>
> On Wed, Oct 15, 2014 at 4:11 PM, Jin Guojun <jguojun at sbcglobal.net> wrote:
>
>> The latest xorg 1.7.7 seems too smart to configure. It always uses what it
>> thinks and ignores what xorg.conf file tells to do.
>>
>>
>> I am using Vesa driver on 8.4-R / 10.1-RC amd kernel on the same hardware
>> (ASUS A88XM-A motherboard) and experienced this difficulty.
>>
>> Two monitors: one has 1600x900 resolution and the other has 1920x1080 res.
>> When attaching 1600x900 monitor to the system, xorg-1.7.7 X server
>> configures the screen as 1600x900, which is nice and it is what I wanted.
>> When connecting 1920x1080 monitor to the system, X server configures
>> screen as 1920x1080, which is correct, but is will not give 1600x900
>> resolution regardless if the Modes "1600x900" is in Screen section in
>> xorg.conf file.
>>
>> If attaching both monitors to the system, then both monitors will be
>> configured as 1600x900, thus both monitors are capable to work in 1600x900
>> resolution.
>>
>> Now, how to tell (force) X server to use 1600x900 resolution for the
>> 1920x1080 monitor?
>>
>> -Jin
>
>
> This is not an X or Xorg issue, I'm afraid. The problem is that ASUS
> has not updated the video BIOS for wide screen displays and, when
> using VESA, only BIOS supported display sizes will work. Some vendors,
> e.i. HP, have updated the BIOS on some systems to support wide screen
> sizes. Lenovo had not when support for Sandy Bridge Intel graphics
> became available. I keep meaning to switch the X server to VESA and
> see if the latest BIOS upgrade fixes this, but I have not gotten to
> it. This is particularly annoying as in both the HP and Lenovo cases I
> am talking about laptops with wide-screen displays, so VESA did not
> work right on the built-in display. I suspect it is less likely to
> work on a system that does not come with a display.
>
> There is simply no work-around for this. It is seems really silly in
> this day of wide-screen display being the norm, but it cost money to
> re-work BIOS and since Windows and Linux support the built-in graphics
> on almost all boards.
>
> I suspect you only hope is to move to a reasonable new FreeBSD
> supporting KMS for Radeon devices. I believe you need to add
> WITH_GALLIUM=YES to /etc/make.conf (echo "WITH_GALLIUM=YES" >>
> /etc/make.conf) before building the kernel. You will also need to
> update old xorg ports as NEW_XORG was only made default very recently.

Sorry for the misinformation. I should have resized that 1600x900 is
also wide screen. It does not take much arithmetic to see that it is a
16:9 aspect ratio. I also mis-read the problem description and see
that it is almost certainly not a BIOS issue.

Try using xrandr(1) to check it out. It will tel you what resolutions
are supported and will let you set it to any supported values. The man
page is pretty complete. You can use --addmode to add modes and
--newmode to define additional mode lines. (Be careful with the latter
as it can cause damage if it is set values out of the specs of the
display.) The xrandr command with no arguments or options provides the
list of modes and output names. You need the output name for to set
the mode.
xrandr --output OUTPUT_NAME --mode 1600x900
xrandr --addmode OUTPUT_NAME 1600x900

Again, sorry for not reading your message more carefully. Note that
the monitor may not tell X that 1600x900 is available. Oh, and VESA
will not provide much in the way of performance, though for almost
anything that is not graphics intensive, it should be OK.
--
R. Kevin Oberman, Network Engineer, Retired
E-mail: rkoberman at gmail.com