amdgpu crashes in get_ss_info_from_atombios()

[Jiri Slaby <jirislaby@kernel.org>]

Hi,

SUSE received a bug report:
https://bugzilla.suse.com/show_bug.cgi?id=1271175

get_ss_info_from_atombios() crashes in 7.1.2.

calc_pll_cs->ctx (dc_context) is NULL while trying to log by the first 
DC_LOG_SYNC() in get_ss_info_from_atombios():
                 if (as_signal == AS_SIGNAL_TYPE_HDMI
                                 && 
ss_info_cur->spread_spectrum_percentage > 6){
                         /* invalid input, do nothing */
                         DC_LOG_SYNC(
                                 "Invalid SS percentage ");
                         DC_LOG_SYNC(
                                 "for HDMI in ATOMBIOS info Table!!!\n");
                         continue;
                 }




Note dce110_clk_src_construct() calls:
   -> ss_info_from_atombios_create()
     -> get_ss_info_from_atombios()   <- uses calc_pll_cs->ctx
   -> calc_pll_max_vco_construct()    <- sets calc_pll_cs->ctx AFAICT

calc_pll_cs->ctx should not be used in the former, or something.





This was likely introduced by:
commit 1296423bf23c7a58133970e223b1f47ec6570308
Author: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Date:   Tue Feb 20 17:42:50 2018 -0500

     drm/amd/display: define DC_LOGGER for logger





Before the commit,
   clk_src->base.ctx->logger
was used in get_ss_info_from_atombios(). The commit unified all users to 
use:
   clk_src->ctx->logger

The former is set at the beginning of dce110_clk_src_construct() (before 
the crash location). The latter only in calc_pll_max_vco_construct() 
(after the crash location).


Any ideas how to fix this? Redefine DC_LOGGER to clk_src->base in 
get_ss_info_from_atombios()?


I'm not sure if this is a regression and there is some underlying issue 
provoking the "Invalid SS percentage" dump -- asked in the bug and 
waiting for a reply.

thanks,
-- 
js
suse labs