drm/mediatek: dp: drm_err => dev_err in HPD path to avoid NULL ptr

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: dp: drm_err => dev_err in HPD path to avoid NULL ptr The function mtk_dp_wait_hpd_asserted() may be called before the `mtk_dp->drm_dev` pointer is assigned in mtk_dp_bridge_attach(). Specifically it can be called via this callpath: - mtk_edp_wait_hpd_asserted - [panel probe] - dp_aux_ep_probe Using "drm" level prints anywhere in this callpath causes a NULL pointer dereference. Change the error message directly in mtk_dp_wait_hpd_asserted() to dev_err() to avoid this. Also change the error messages in mtk_dp_parse_capabilities(), which is called by mtk_dp_wait_hpd_asserted(). While touching these prints, also add the error code to them to make future debugging easier.

References

• https://git.kernel.org/stable/c/13ec849fd2eab808ee8eba2625df7ebea3b85edf
• https://git.kernel.org/stable/c/57a9fb47551b33cde7b76d17c0072c3b394f4620
• https://git.kernel.org/stable/c/2fda391ef7a701748abd7fa32232981b522c1e07
• https://git.kernel.org/stable/c/149a5c38436c229950cf1020992ce65c9549bc19
• https://git.kernel.org/stable/c/106a6de46cf4887d535018185ec528ce822d6d84