From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vincent Pelletier Subject: Bisect: i2c regression in 63daa9589cb88617d9cc8a0b0282564682a975b7 Date: Sun, 1 Jan 2012 22:38:25 +0100 Message-ID: <201201012238.25620.plr.vincent@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nouveau-bounces+gcfxn-nouveau=m.gmane.org-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Errors-To: nouveau-bounces+gcfxn-nouveau=m.gmane.org-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org To: nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Cc: Ben Skeggs List-Id: nouveau.vger.kernel.org Hi. Updating nouveau module to a newer git revision, I noticed I lost hwmon. I ran a bisect, which identified 63daa9589cb88617d9cc8a0b0282564682a975b7 as being the first bad commit. Adding printk traces, I saw that probing i2c bus 3 for sensors always failed with -EIO (no ack from slave). After reading the code, remembering how i2c works and reading sample code on wikipedia, I couldn't identify any algorythmic problem. So I gave a try at changing delays. I doubled T_RISEFALL and T_HOLD, and the adt7473 chip could be detected & used again. I haven't tested other combination, nor tried to link those delays with any datasheet. My card is a GTX 280. Regards, -- Vincent Pelletier