Kernel stuck at HDMI display registration in I.MX6Q

[pratik_manvar]

I am using Linux 4.1.15 kernel. I found a very strange problem. When I registered HDMI, the kernel will be stuck in the HDMI driver. When I have placed the debugs, I come to know that it stuck at "mxc_hdmi_edid_rebuild_modelist" function.

Please see below logs:

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Starting kernel ...

Booting Linux on physical CPU 0x0
Linux version 4.1.15 (pratik@VM153) (gcc version 5.3.0 (GCC) ) #2 SMP PREEMPT Tue Aug 20 17:56:30 IST 2019
CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c53c7d
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine model: Freescale i.MX6 Quad HPK Board
Reserved memory: created CMA memory pool at 0x6a000000, size 320 MiB
Reserved memory: initialized node linux,cma, compatible id shared-dma-pool
Memory policy: Data cache writealloc
PERCPU: Embedded 12 pages/cpu @ee702000 s16908 r8192 d24052 u49152
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 520720
Kernel command line: console=ttymxc3,115200 rootwait rw
PID hash table entries: 4096 (order: 2, 16384 bytes)
Dentry cache hash table entries: 262144 (order: 8, 1048576 bytes)
Inode-cache hash table entries: 131072 (order: 7, 524288 bytes)
Memory: 1713940K/2097152K available (8904K kernel code, 553K rwdata, 3452K rodata, 23152K init, 449K bss, 55532K reserved, 327680K cma-reserved, 270336K highmem)
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    vmalloc : 0xf0000000 - 0xff000000   ( 240 MB)
    lowmem  : 0x80000000 - 0xef800000   (1784 MB)
    pkmap   : 0x7fe00000 - 0x80000000   (   2 MB)
    modules : 0x7f000000 - 0x7fe00000   (  14 MB)
      .text : 0x80008000 - 0x80c193b8   (12357 kB)
      .init : 0x80c1a000 - 0x822b6000   (23152 kB)
      .data : 0x822b6000 - 0x823407c0   ( 554 kB)
       .bss : 0x82343000 - 0x823b3680   ( 450 kB)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
Preemptible hierarchical RCU implementation.
   Additional per-CPU info printed with stalls.
NR_IRQS:16 nr_irqs:16 16
L2C-310 erratum 769419 enabled
L2C-310 enabling early BRESP for Cortex-A9
L2C-310 full line of zeros enabled for Cortex-A9
L2C-310 ID prefetch enabled, offset 16 lines
L2C-310 dynamic clock gating enabled, standby mode enabled
L2C-310 cache controller enabled, 16 ways, 1024 kB
L2C-310: CACHE_ID 0x410000c7, AUX_CTRL 0x76470001
mxc_clocksource_init 3000000
Switching to timer-based delay loop, resolution 333ns
sched_clock: 32 bits at 3000kHz, resolution 333ns, wraps every 715827882841ns
clocksource mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 637086815595 ns
Console: colour dummy device 80x30
Calibrating delay loop (skipped), value calculated using timer frequency.. 6.00 BogoMIPS (lpj=30000)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 4096 (order: 2, 16384 bytes)
Mountpoint-cache hash table entries: 4096 (order: 2, 16384 bytes)
CPU: Testing write buffer coherency: ok
CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
Setting up static identity map for 0x10008280 - 0x100082d8
CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
Brought up 4 CPUs
SMP: Total of 4 processors activated (24.00 BogoMIPS).
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4
clocksource jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
pinctrl core: initialized pinctrl subsystem
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
cpuidle: using governor ladder
cpuidle: using governor menu
CPU identified as i.MX6Q, silicon rev 0.6
anatop_regulator 20c8000.anatop:regulator-vddcore@140: Failed to read a valid default voltage selector.
anatop_regulator: probe of 20c8000.anatop:regulator-vddcore@140 failed with error -22
anatop_regulator 20c8000.anatop:regulator-vddsoc@140: Failed to read a valid default voltage selector.
anatop_regulator: probe of 20c8000.anatop:regulator-vddsoc@140 failed with error -22
hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers.
hw-breakpoint: maximum watchpoint size is 4 bytes.
initialized HPK pin-bootconfig driver
imx6q-pinctrl 20e0000.iomuxc: initialized IMX pinctrl driver
mxs-dma 110000.dma-apbh: initialized
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
2000000.aips-bus:usbphy_nop1 supply vcc not found, using dummy regulator
2000000.aips-bus:usbphy_nop2 supply vcc not found, using dummy regulator
i2c i2c-0: IMX I2C adapter registered
i2c i2c-0: can't use DMA
i2c i2c-1: Invalid 7-bit I2C address 0xa0
i2c i2c-1: of_i2c: Failure registering /soc/aips-bus@02100000/i2c@021a4000/edid@a0
i2c i2c-1: IMX I2C adapter registered
i2c i2c-1: can't use DMA
i2c i2c-2: IMX I2C adapter registered
i2c i2c-2: can't use DMA
Linux video capture interface: v2.00
pps_core: LinuxPPS API ver. 1 registered
pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
PTP clock support registered
imx-ipuv3 2400000.ipu: IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
imx-ipuv3 2800000.ipu: IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
Advanced Linux Sound Architecture Driver Initialized.
Bluetooth: Core ver 2.20
NET: Registered protocol family 31
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
Bluetooth: L2CAP socket layer initialized
Bluetooth: SCO socket layer initialized
Switched to clocksource mxc_timer1
NET: Registered protocol family 2
TCP established hash table entries: 16384 (order: 4, 65536 bytes)
TCP bind hash table entries: 16384 (order: 5, 131072 bytes)
TCP: Hash tables configured (established 16384 bind 16384)
UDP hash table entries: 1024 (order: 3, 32768 bytes)
UDP-Lite hash table entries: 1024 (order: 3, 32768 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
CPU PMU: Failed to parse /soc/pmu/interrupt-affinity[0]
hw perfevents: enabled with armv7_cortex_a9 PMU driver, 7 counters available
imx rpmsg driver is registered.
Bus freq driver module loaded
futex hash table entries: 1024 (order: 4, 65536 bytes)
VFS: Disk quotas dquot_6.6.0
VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
NFS: Registering the id_resolver key type
Key type id_resolver registered
Key type id_legacy registered
jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
fuse init (API version 7.23)
bounce: pool size: 64 pages
io scheduler noop registered
io scheduler deadline registered
io scheduler cfq registered (default)
imx-weim 21b8000.weim: Driver registered.
backlight supply power not found, using dummy regulator
mxc_hdmi 20e0000.hdmi_video: Detected HDMI controller 0x13:0xa:0xa0:0xc1
fbcvt: Aspect ratio not CVT standard
fbcvt: 720x480@60: CVT Name - Not a CVT standard - 0.345 Mega Pixel Image

mxc_sdc_fb fb@0: registered mxc display driver hdmi

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Below the snippet of code where I think it is stuck.

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static void mxc_hdmi_edid_rebuild_modelist(struct mxc_hdmi *hdmi)

{

    int i;

    struct fb_videomode *mode;

    dev_dbg(&hdmi->pdev->dev, "%s\n", __func__);

    console_lock();

    fb_destroy_modelist(&hdmi->fbi->modelist);

    fb_add_videomode(&vga_mode, &hdmi->fbi->modelist);

    ...

    ...

}

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It seems that after console_lock() function, it will not come out. Have anyone ever encountered this kind of problem? I have been debugging since last two days and I don't know where the problem is.

Thank you very much!

Regards,

Pratik Manvar 

[igorpadykov]

Hi Pratik

one can check similar issue on

HDMI connection causes crash on i.MX6 Solo 

and try with latest nxp linux:

Linux L4.14.98    Linux L4.14.98_2.0.0 Documentation
linux-imx - i.MX Linux kernel 

Best regards
igor
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[pratik_manvar]

Thank you very much Mr. Igor.

Moreover, we will also test the latest kernel as per your suggestion.

Thanks,

Pratik Manvar