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11:57:51.8530 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: d9995866-0d9b-4251-8315-093f062abab4 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: rzfoStCNFR2sXkX6cd/241jjVbyiBMT7BHpkGSLDKJXKyRhtBnWbpbUZI8OoZckodu1O5WrpkDtE24yfHOP3TFzI6yn7oZ06sM4bCnLR4BY= X-MS-Exchange-Transport-CrossTenantHeadersStamped: GVAP278MB0422 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CDE13A77 smtp.mailfrom=francesco.dolcini@toradex.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: toradex.com Content-Type: text/plain; charset=WINDOWS-1252 Content-Disposition: inline Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org + oleksandr.suvorov@foundries.io Hello all, On Tue, Jul 12, 2022 at 12:05:04PM +0200, Francesco Dolcini wrote: > On Tue, Jul 12, 2022 at 11:05:14AM +0200, Uwe Kleine-König wrote: > > In which situations does this help? Please mention these in the > > commit log. > I'll do I did some investigation on this, unfortunately we have this change laying around since 1 year, it was written by Oleksandr, and in the meantime he moved to a new company. I added him to this email thread, so he can comment in case he remembers more. We introduced this change while working on OV5640 camera sensor on an apalis-imx6q evaluation board, without this change we had some sporadic i2c communication issues. Unfortunately I do not have any better details. To me looks like having some (3? 5?) retry as a default is somehow more reasonable than to never retry, not sure if this should be implemented as a default for all the i2c adapters. From what I was able to see that would not be a trivial change (the retry parameter is coming from the i2c_imx driver, there is no obvious way to have a default in the i2c core). Would it work for you to keep the change as it is (just getting rid of the useless define) and add a little bit more blurb to the commit message to include the various comments collected so far? Francesco