From: Wolfram Sang <wsa@kernel.org>
To: Sanford Rockowitz <rockowitz@minsoft.com>
Cc: linux-i2c@vger.kernel.org
Subject: Re: i2c-dev mismatch with proprietary nvidia driver
Date: Wed, 28 Sep 2022 21:16:20 +0200 [thread overview]
Message-ID: <YzSdhCrwjPwMr4DI@shikoro> (raw)
In-Reply-To: <6330FC96.5030908@minsoft.com>
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Hi,
> At approximately line 41 of nvidia driver file nv-i2c.c, in function
> nv_i2c_algo_master_transfer(), there's an if-test for symbol I2C_M_DMA_SAFE.
> If the symbol is not defined, a call to the function with the bit set fails
> with error -EINVAL. The file includes "linux/i2c.h", so apparently there are
> versions of I2c.h in which the flag is undefined.
I2C_M_DMA_SAFE is a hint for controller drivers that the buffer is DMA
capable. It is not something the controller driver needs to support
actively. Bailing out on this flag is wrong. Do I need to mention that
such misconceptions are the super-downside of out-of-tree drivers? (I
know that you are only a user of this driver, so not your fault)
Happy hacking,
Wolfram
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next prev parent reply other threads:[~2022-09-28 19:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-26 1:12 i2c-dev mismatch with proprietary nvidia driver Sanford Rockowitz
2022-09-28 19:16 ` Wolfram Sang [this message]
2022-09-29 16:21 ` Sanford Rockowitz
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