From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: linux-i2c@vger.kernel.org, jikos@kernel.org,
aaron.ma@canonical.com, admin@kryma.net,
benjamin.tissoires@redhat.com, hdegoede@redhat.com,
hn.chen@weidahitech.com, jarkko.nikula@linux.intel.com,
kai.heng.feng@canonical.com, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com,
vicamo.yang@canonical.com, wsa@kernel.org
Subject: Re: [PATCH v2 2/4] i2c: designware: Ensure tx_buf_len is nonzero for SMBus block reads
Date: Thu, 17 Sep 2020 15:47:30 +0300 [thread overview]
Message-ID: <20200917124730.GL3956970@smile.fi.intel.com> (raw)
In-Reply-To: <20200917052256.5770-3-sultan@kerneltoast.com>
On Wed, Sep 16, 2020 at 10:22:54PM -0700, Sultan Alsawaf wrote:
> From: Sultan Alsawaf <sultan@kerneltoast.com>
>
> The point of adding a byte to len in i2c_dw_recv_len() is to make sure
> that tx_buf_len is nonzero, so that i2c_dw_xfer_msg() can let the i2c
> controller know that the i2c transaction can end. Otherwise, the i2c
> controller will think that the transaction can never end for block
> reads, which results in the stop-detection bit never being set and thus
> the transaction timing out.
>
> Adding a byte to len is not a reliable way to do this though; sometimes
> it lets tx_buf_len become zero, which results in the scenario described
> above. Therefore, just directly ensure tx_buf_len cannot be zero to fix
> the issue.
I got only patch 2/4, where the other 3 along with cover letter?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-09-17 12:56 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 5:22 [PATCH v2 0/4] i2c-hid: Save power by reducing i2c xfers with block reads Sultan Alsawaf
2020-09-17 5:22 ` [PATCH v2 1/4] i2c: designware: Fix transfer failures for invalid SMBus " Sultan Alsawaf
2020-09-17 5:22 ` [PATCH v2 2/4] i2c: designware: Ensure tx_buf_len is nonzero for " Sultan Alsawaf
2020-09-17 12:47 ` Andy Shevchenko [this message]
2020-09-17 13:44 ` Jarkko Nikula
2020-09-17 14:45 ` Andy Shevchenko
2020-09-17 5:22 ` [PATCH v2 3/4] i2c: designware: Allow SMBus block reads up to 255 bytes in length Sultan Alsawaf
2020-09-17 20:57 ` Wolfram Sang
2020-09-17 23:12 ` Sultan Alsawaf
2020-09-17 5:22 ` [PATCH v2 4/4] HID: i2c-hid: Use block reads when possible to save power Sultan Alsawaf
2020-09-17 14:02 ` [PATCH v2 0/4] i2c-hid: Save power by reducing i2c xfers with block reads Andy Shevchenko
2020-09-23 13:59 ` Jarkko Nikula
2020-09-22 9:19 ` Jiri Kosina
2020-09-22 11:36 ` Wolfram Sang
2020-09-22 19:59 ` Jiri Kosina
2020-09-23 6:02 ` Sultan Alsawaf
2020-10-16 11:16 ` Hans de Goede
2020-10-16 15:24 ` Sultan Alsawaf
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