On Wed, 13 Nov 2024, Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> wrote: > On (24/10/31 19:51), Sergey Senozhatsky wrote: >> intel_ddi_init() may skip connector initialization, for instance, >> both intel_ddi_init_dp_connector() and intel_ddi_init_hdmi_connector() >> are optional. This leads to situation that ->attached_connector may >> be NULL for some connectors. For instance, on my setup 'DDI A/PHY A' >> and 'DDI TC1/PHY TC1' are not initialized. >> >> However, functions like intel_dp_dual_mode_set_tmds_output() and >> friends don't take this into consideration. This leads to NULL >> ptr-derefs: >> >> KASAN: null-ptr-deref in range [0x0000000000000848-0x000000000000084f] >> RIP: 0010:intel_hdmi_encoder_shutdown+0x105/0x230 >> Call Trace: >> <TASK> >> i915_driver_shutdown+0x2d8/0x490 >> pci_device_shutdown+0x83/0x150 >> device_shutdown+0x4ad/0x660 >> __se_sys_reboot+0x29c/0x4d0 >> do_syscall_64+0x60/0x90 >> >> Add a new helper to avoid NULL ->attached_connector derefs and >> switch some intel_hdmi function to it. I'm not sure if we need >> to switch all or just intel_dp_dual_mode_set_tmds_output() (I >> have only seen this one doing NULL derefs so far). > > Folks, any more comments / opinions on this? > What should be the way forward? Ville, we handle intel_ddi_init_dp_connector() failures but not intel_ddi_init_hdmi_connector() failures. Do you recall if there's a reason for that? Something like a dual-mode port where DP works but HDMI gets rejected because of bogus VBT info? My gut feeling is to propagate errors from intel_hdmi_init_connector() and handle them properly in g4x_hdmi_init() and intel_ddi_init_hdmi_connector(). Of course, we have cases where hdmi is just not initialized on DDI, and those should be handled. But I don't think hdmi->attached_connector != NULL is really the right check for that. BR, Jani. -- Jani Nikula, Intel
