From: Greg KH <gregkh@linuxfoundation.org>
To: sun jian <sun.jian.kdev@gmail.com>
Cc: linux-staging@lists.linux.dev, sudipm.mukherjee@gmail.com,
teddy.wang@siliconmotion.com, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH v2] staging: sm750fb: fix unused tmp in sw_i2c_wait
Date: Mon, 5 Jan 2026 10:12:30 +0100 [thread overview]
Message-ID: <2026010555-surely-uncheck-bac2@gregkh> (raw)
In-Reply-To: <CABFUUZHRz919=C=fmMqH1sQcURbm+qiQB795xWPCd9Rax_M4ZQ@mail.gmail.com>
On Mon, Jan 05, 2026 at 04:57:48PM +0800, sun jian wrote:
> Hi Greg,
>
> Sorry about that — I mistakenly replied only to you.
>
> As you pointed out, sw_i2c_wait() sits on the bit-banged I2C GPIO
> transitions, so changing the delay semantics without hardware validation
> is risky. I don't have access to the hardware to validate timing/behavior,
> and I can't justify that udelay(1) is equivalent to the existing loop.
>
> Please ignore v2 (and v1). I won't resend a warning-only workaround.
>
> If someone with the hardware can help validate a proper fix (e.g. a
> well-justified time-based delay, or reworking this to use a proper I2C
> bit-banging helper), I'm happy to revisit.
A time-based one is going to be the correct solution as every cpu will
run that "let's count some numbers" loop at a different speed :(
thanks,
greg k-h
prev parent reply other threads:[~2026-01-05 9:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 2:10 [PATCH] staging: sm750fb: fix unused tmp in sw_i2c_wait Sun Jian
2026-01-05 6:28 ` Greg KH
2026-01-05 7:49 ` [PATCH v2] " Sun Jian
2026-01-05 8:05 ` Greg KH
2026-01-05 8:57 ` sun jian
2026-01-05 9:12 ` Greg KH [this message]
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