Re: [PATCH] boot_constraint: Add constraints for earlycon on dragonboard 410c

[Sai Prakash Ranjan]

On 11/16/2018 4:23 PM, Viresh Kumar wrote:
> Hi,
>
> On 16-11-18, 16:16, Sai Prakash Ranjan wrote:
> > iface clock is shared with other drivers, which may reconfigure
> > this before the serial driver comes up. This may lead to
> > crashes like the one below where GCC_BLSP1_AHB_CLK is same across
> > multiple drivers like bam dma.
> >
> > <0>[    3.164471] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP
> > <4>[    3.164479] Modules linked in:
> > <4>[    3.164495] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc8-00008-ge033b9909fff-dirty #175
> > <4>[    3.164501] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> > <4>[    3.164508] pstate: 40000085 (nZcv daIf -PAN -UAO)
> > <4>[    3.164514] pc : msm_read.isra.2+0x20/0x50
> > <4>[    3.164520] lr : msm_read.isra.2+0x1c/0x50
> > <4>[    3.164526] sp : ffff000008033a50
> > <4>[    3.164531] x29: ffff000008033a50 x28: ffff000009486018
> > <4>[    3.164548] x27: 0000000000000001 x26: ffff7dfffe7ff070
> > <4>[    3.164565] x25: 0000000000000034 x24: ffff000009486000
> > <4>[    3.164582] x23: 0000000000000000 x22: ffff00000978e190
> > <4>[    3.164599] x21: ffff0000095e8228 x20: 0000000000000034
> > <4>[    3.164616] x19: ffff7dfffe7ff008 x18: ffffffffffffffff
> > <4>[    3.164632] x17: 0000000000000000 x16: 0000000000000000
> > <4>[    3.164649] x15: ffff0000094a96c8 x14: ffff00008978e6bf
> > <4>[    3.164666] x13: ffff00000978e6cd x12: 0000000000000038
> > <4>[    3.164683] x11: ffff0000094c6000 x10: 0000000000000c24
> > <4>[    3.164699] x9 : ffff80003c89b400 x8 : ffff000008033970
> > <4>[    3.164716] x7 : ffff80000eb04100 x6 : 00000000000af304
> > <4>[    3.164732] x5 : 0000000000000c40 x4 : ffff80003c06f000
> > <4>[    3.164750] x3 : ffff80003c89b498 x2 : 0000000000000000
> > <4>[    3.164766] x1 : ffff80003ca68000 x0 : 0000000000000800
> > <0>[    3.164785] Process swapper/0 (pid: 1, stack limit = 0x(____ptrval____))
> > <4>[    3.164791] Call trace:
> > <4>[    3.164797]  msm_read.isra.2+0x20/0x50
> > <4>[    3.164804]  msm_reset_dm_count+0x44/0x80
> > <4>[    3.164810]  __msm_console_write+0x1c8/0x1d0
> > <4>[    3.164816]  msm_serial_early_write_dm+0x3c/0x50
> > <4>[    3.164823]  console_unlock.part.6+0x468/0x528
> > <4>[    3.164829]  vprintk_emit+0x210/0x218
> > <4>[    3.164835]  vprintk_default+0x48/0x58
> > <4>[    3.164841]  vprintk_func+0xf0/0x1c0
> > <4>[    3.164847]  printk+0x74/0x94
> > <4>[    3.164853]  sci_init+0x24/0x3c
> > <4>[    3.164859]  do_one_initcall+0x54/0x248
> > <4>[    3.164866]  kernel_init_freeable+0x210/0x378
> > <4>[    3.164872]  kernel_init+0x18/0x118
> > <4>[    3.164878]  ret_from_fork+0x10/0x1c
> > <0>[    3.164884] Code: aa1e03e0 8b214273 97e616f7 d503201f (b9400260)
> >
> > Link: https://lore.kernel.org/lkml/1cae8f10-55f5-20ce-9105-30af6f88bd6e@xxxxxxxxxxxxxx/
> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> >
> > ---
> >
> > This is purely dependent on boot constraint subsystem by Viresh.
> >
> > Link: https://lore.kernel.org/lkml/cover.1519380923.git.viresh.kumar@xxxxxxxxxx/
> > ---
> >   drivers/soc/qcom/boot_constraint.c | 15 +++++++++++++++
> >   1 file changed, 15 insertions(+)
>
> Nice to see that the new subsystem has fixed your issue as well and
> thanks for the patch. I am afraid though that this patch isn't going
> to get merged anywhere as the subsystem isn't merged yet as Greg
> wasn't too confident [1] about it. We are looking for more use-cases
> apart from earlycon and clcd.

Hi Viresh,

Thanks for your time.

I wanted to get this patch out so that once we have enough use cases,
maybe we can add this as well.

Thanks,
Sai

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