Re: [PATCH for rc] ufs: core: Configure MCQ after link startup

["Peter Wang (王信友)" <peter.wang@mediatek.com>]

On Thu, 2025-12-18 at 15:07 -0800, Bart Van Assche wrote:
> Commit f46b9a595fa9 ("scsi: ufs: core: Allocate the SCSI host
> earlier")
> did not only cause scsi_add_host() to be called earlier. It also
> swapped
> the order of link startup and enabling and configuring MCQ mode.
> Before
> that commit, the call chains for link startup and enabling MCQ were
> as
> follows:
> 
> ufshcd_init()
>   ufshcd_link_startup()
>   ufshcd_add_scsi_host()
>     ufshcd_mcq_enable()
> 
> Apparently this change causes link startup to fail. Fix this by
> configuring
> MCQ after link startup has completed.
> 
> Reported-by: Nitin Rawat <nitin.rawat@oss.qualcomm.com>
> Fixes: f46b9a595fa9 ("scsi: ufs: core: Allocate the SCSI host
> earlier")
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>

Hi Bart,

It seems strange to me that ufshcd_mcq_enable is called before
ufshcd_link_startup.

In driver development, configuration (config) should generally
be done before enabling (enable) the hardware.
Reason:
Configuring first ensures the hardware operates correctly and
avoids unexpected behavior or safety issues.

Typical steps:
1. Set registers/parameters
2. Initialize resources
3. Configure interrupts/DMA
4. Enable the hardware

So, do you also consider moving ufshcd_mcq_enable after 
ufshcd_config_mcq?

Thanks.
Peter