Hi,
On 07-11-16 09:11, Maxime Ripard wrote:
Hi,
On Sun, Nov 06, 2016 at 06:54:11PM +0800, Icenowy Zheng wrote:
06.11.2016, 18:13, "Hans de Goede" <[email protected]>:
Hi,
On 06-11-16 04:35, Chen-Yu Tsai wrote:
Hi everyone,
I spent a bit of time adding DRM support for the A23 yesterday.
Icenowy successfully got DRM working for the A33 Q8 tablets.
It occurred to me today that we have 2 types of panels for the
A33 Q8 tablets, one is 800x480 and the other is 1024x600. However
we are currently sharing the same dts file for both, and only
U-boot knows about the different resolutions.
I see 2 ways to fix this. One would be to provide a separate
dts file for the 1024x600 variant. The other would be to get
U-boot to patch the dts file.
Either way would require users upgrading U-boot, or at least
their boot scripts in the first case, though.
Any ideas?
Since we already have 2 u-boot configs for this having 2 dts files
seems like the best solution to me.
Maybe for compatibility we need 3 dts files...
1. Q8 dts : everything except display (For users migrated from the old
single-dt time)
2. Q8 800x480 dts : #include <Q8 dts>, /panel/compatible = "urt,umsh-8596md-t"
/* This compatible is what Chen-Yu used in sun5i-q8, and I used it also on my
A33 Q8 */
3. Q8 1024x600 dts : #include <Q8 dts>, /panel/compatible = foo
I'm not sure why we need both actually.
Even if the resolutions are the same, chances are the panel won't be,
and will have different timings.
So far all 800x480 and all 1024x600 q8 a23/a33 tablets work
with a single set of timings (per resolution).
I guess your plan is simply to use different compatible,
There is no plan, since a single set of timing works for
all tablets encountered so far).
then we don't really need two different device
trees in the first place, do we?
It all depends on how closely we want to couple u-boot and the kernel.
Either we need to have u-boot patch in the right panel compatible, but
only on q8_a33_tablet configs, or we stick with the one defconfig
1 dts pattern used everywhere.
Basically the problem is that currently both:
configs/q8_a33_tablet_1024x600_defconfig
configs/q8_a33_tablet_800x480_defconfig
Refer to the same dts, fixing that is really easy and
consistent with what we do in the other 100 sunxi defconfig-s
u-boot now has. Where as hot patching the panel compatible
requires q8_a33_tablet specific code in u-boot which I
would rather avoid.
Regards,
Hans
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