Re: [PATCH v4 1/4] clk: fractional-divider: Export approximation algorithm to the CCF users
flat view
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: 2021-09-07 17:54:14
Also in:
linux-acpi, linux-clk, linux-rockchip, lkml
On Tue, Sep 07, 2021 at 10:44:00AM -0500, Chris Morgan wrote:
From: Chris Morgan <redacted> Unfortunately, I can confirm this breaks the DSI panel on the Rockchip PX30 (and possibly other SoCs). Tested on my Odroid Go Advance. When I revert 4e7cf74fa3b2 "clk: fractional-divider: Export approximation algorithm to the CCF users" and 928f9e268611 "clk: fractional-divider: Hide clk_fractional_divider_ops from wide audience" the panel begins working again as expected on the master branch. It looks like an assumption is made in the vop_crtc_mode_fixup() function in the rockchip_drm_vop.c that gets broken with this change. Specifically, the function says in the comments "When DRM gives us a mode, we should add 999 Hz to it.". I believe this is no longer true after this clk change, and when I remove the + 999 from the function the DSI panel works again. Note that I do not know the implications of removing this 999 aside from that it fixes the DSI panel on my PX30 after this change, so I don't know if it's a positive change or not. Thank you.
Thank you for the report! I'll check this. Perhaps Heiko can help with testing as well on his side. -- With Best Regards, Andy Shevchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel