Il 03/03/26 08:56, CK Hu (胡俊光) ha scritto:
On Wed, 2026-02-25 at 09:15 +0100, Luca Leonardo Scorcia wrote:
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The mt8167 DSI controller is fully compatible with the one found in
mt2701. Device tree documentation is already present upstream.
If mt8167 DSI is fully compatible with mt2701 DSI, I think the binding document
and device tree should be modified.
In device tree,
compatible = "mediatek,mt8167-dsi", "mediatek,mt2701-dsi";
And this patch is not necessary.
Hi, if I understand your review correctly that's what v2 [1] of this
patch did, but the change was rejected during review.
As far as I can see there is no win-win solution here. This tricky
situation derives from the fact that in last year's submissions the
change was only partially merged - the bindings went upstream while
the driver did not, and now we have to work around this. In v3 I tried
to address the issue by actually implementing what the binding
document says.
I'll be happy to resubmit v4 but I need to know what's the consensus here.
You mean Krzysztof's comment?
He has two comment.
The first is 'remove'. You actually not remove "mediatek,mt8167-dsi". You
change it.
The second is about fallback. I'm also not sure why he says it's NAK. Also a
bad wording?
After Angelo's comment, Krzysztof does not response.
I also do not know what Krzysztof think.
I agree with Angelo. Single "mediatek,mt8167-dsi" does not reflect the hardware
compatible but fallback does.
Maybe describe more information (hardware) to Krzysztof, and ask what's the
better way to do.
First of all: I would be happy with having
compatible = "mediatek,mt8167-dsi", "mediatek,mt2701-dsi";
in the devicetree, and to drop this patch - but that's not possible, check
below.
The problem that Krzysztof was raising is that the bindings currently define
the "mediatek,mt8167-dsi" as single compatible with no fallback, and removing
it would break the ABI (as the bindings are not used only for Linux, but also
for bootloaders).
Even though I can try my best to convince him, this is a real problem: mistakes
were made in the past, and the only way to get the mt8167-dsi supported right
now is to, unfortunately, add the compatible in mtk_dsi.c.
I don't like that, and I see that you (CK) don't as well, but that's the result
of past mistakes... and apparently we can't do anything about this if not to
*uselessly clutter the driver* with that.
So, that said...
I'm sad to say that this patch is the only way to get this SoC probed by mtk_dsi
and that there's no other way around it, because the bindings maintainers are
forbidding us from removing the bad compatible (which was *never* used anyway)
from there and making it right with allowing it only under 2701 fallback.
I'm moving krzk to the To: field of this email in hope to get back a reply that
sounds like "you misunderstood me, you can do it", but I'm not positive about
this.
Krzysztof, please confirm or deny what I said.
Regards,
Angelo
Regards,
CK
Thanks!
[1]
https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/ff920a7cc94f2b0c03d4bb55142030fded30d07c.1771258407.git.l.scor...@gmail.com/__;!!CTRNKA9wMg0ARbw!lIBnCRkybM1oxoARb70JlLMPlXHKqW9dwSmVqXGsvj3LE9hsWuINkPgtrlr8Jl8-atOvzYoMjtavHOr3$
Signed-off-by: Luca Leonardo Scorcia <[email protected]>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
b/drivers/gpu/drm/mediatek/mtk_dsi.c
index af4871de9e4c..ad10e86b161d 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -1301,6 +1301,7 @@ static const struct mtk_dsi_driver_data
mt8188_dsi_driver_data = {
static const struct of_device_id mtk_dsi_of_match[] = {
{ .compatible = "mediatek,mt2701-dsi", .data = &mt2701_dsi_driver_data
},
+ { .compatible = "mediatek,mt8167-dsi", .data = &mt2701_dsi_driver_data
},
{ .compatible = "mediatek,mt8173-dsi", .data = &mt8173_dsi_driver_data
},
{ .compatible = "mediatek,mt8183-dsi", .data = &mt8183_dsi_driver_data
},
{ .compatible = "mediatek,mt8186-dsi", .data = &mt8186_dsi_driver_data
},
--
2.43.0
--
Luca Leonardo Scorcia
[email protected]
