Re: eMac video modes

[John Paul Adrian Glaubitz]

On 4/3/20 10:58 PM, Ed Robbins wrote:
>> 2. I used switchresx on mac OS X to export all the video modes of the eMac
>> monitor, rewrote them into modelines, and then used [3] to generate an EDID
>> bin file (1280x960.bin). It only contains the video mode for the highest
>> resolution, 1280x960@72Hz. The modeline is "1280x960" 122.24 1280 1328
>> 1424 1696 960 961 964 1002 +hsync +vsync.
>> 3. Copy the EDID bin file to /lib/firmware/edid/1280x960.bin
>> 4. Create /usr/share/initramfs-tools/hooks/edid with contents as below
>> (looking at it now, I guess this could actually be done with a one line
>> "install -D" but anyway...)
>>
>> #!/bin/sh
>> mkdir -p ${DESTDIR}/lib/firmware/edid
>> cp -pnL /lib/firmware/edid/1280x960.bin
>> ${DESTDIR}/lib/firmware/edid/1280x960.bin
>> chmod 644 ${DESTDIR}/lib/firmware/edid/1280x960.bin
>>
>> 5. Run "update-initramfs -u" to create the new initramfs

This sounds like a reasonable approach. We would just need to find a
firmware package where the EDID file fits in, see:

> https://packages.debian.org/search?suite=buster&section=all&arch=any&searchon=names&keywords=firmware

> Alternatively, I think the attached kernel patch will do the same thing.
> You would then boot with the parameter:
> drm.edid_firmware=edid/emac_1280x960.bin
> 
> The disadvantage is that it wont work for any kernel, and I guess it is
> unlikely to be accepted upstream by the kernel devs. However most emac
> users will not be building mainline kernels, and I guess you are already
> patching the kernel for powerpc? So this might be the best way, even if
> users have to manually add the boot parameter.

No, we're not rolling a custon kernel. Debian for PowerPC uses the Debian
stock kernel, with all the patches Debian needs.

It could be added as a patch to the kernel package, but it would have be
carried around forever which I don't think is acceptable.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
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`. `'   Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
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