Paul Menzel <pmen...@molgen.mpg.de> 於 2025年5月25日 週日 下午2:01寫道： > > Dear Linux folks, > > > On the older MT8183 device Lenovo IdeaPad Duet Chromebook, running > ChromeOS with their Linux 5.10.x, connecting a 1920x1080 Dell monitor to > a USB-C adapter using HDMI, only the resolution of 1280x720 is > configured, although the adapter also support 1920x1080. It happens with > all adapters, for example, LMP USB-C mini Dock [1]. > > I reported it to the Chromium OS issue tracker [1], and the last comment is: > > > It seems the display pipeline for the internal display (DSI) has > > higher clock rate. Also, the resolution support depends on the > > refresh rate as well, so the claimed 2400x1080 might only work on > > lower refresh rate. > > > > For the external display, the display modes are mostly rejected by > > the pre-defined max_clock_khz in mtk_dpi.c: > > https://elixir.bootlin.com/linux/v6.11.4/source/drivers/gpu/drm/mediatek/mtk_dpi.c#L940 > > Can you confirm this? The font rendering seems not so good in the lower > resolution, and strangely, playing movies these seem to be rendered in > higher resolution (or the monitor or hardware does a good job in > up-scaling).
8183 max_clock_khz is defined in patch [3] by Rex, but this is a prepare patch for mt8192 [4]. I'm not sure that Rex has test it for mt8183. Maybe you could try to enlarge 8183 max_clock_khz and see. [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/mediatek/mtk_dpi.c?h=v6.17-rc1&id=44b07120291c4b7a6722ccb7149f6b9d938cf5a2 [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/mediatek/mtk_dpi.c?h=v6.17-rc1&id=38eaef2dca4ec8dfb9ea84d9dde0f76da5c8caaa Regards, CK > > > Kind regards, > > Paul > > > [1]: https://lmp-adapter.com/product/lmp-usb-c-mini-dock/ > [2]: https://issuetracker.google.com/issues/295666708
