From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Date: Thu, 24 Apr 2014 12:48:26 +0000 Subject: Re: [PATCH 03/13] video: clarify I2C dependencies Message-Id: <12886728.o7TzRXlxjF@wuerfel> List-Id: References: <1398342509-10243-1-git-send-email-peter.griffin@linaro.org> <1398342509-10243-4-git-send-email-peter.griffin@linaro.org> <20140424123235.GS26756@n2100.arm.linux.org.uk> In-Reply-To: <20140424123235.GS26756@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Russell King - ARM Linux Cc: Peter Griffin , linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, Jean-Christophe Plagniol-Villard , Tomi Valkeinen , linux-fbdev@vger.kernel.org, Anatolij Gustschin On Thursday 24 April 2014 13:32:35 Russell King - ARM Linux wrote: > On Thu, Apr 24, 2014 at 01:28:19PM +0100, Peter Griffin wrote: > > From: Arnd Bergmann > > > > We can only use I2C support in frame buffer drivers if > > Either I2C is built-in, or both I2C and the driver itself > > are loadable modules. > > Why? If I2C is a loadable module, and the I2C support of the framebuffer driver is built-in, you get a link error when building vmlinux: drivers/built-in.o: In function `cyberpro_pci_remove': :(.text+0x1ea5c): undefined reference to `i2c_del_adapter' drivers/built-in.o: In function `cyberpro_pci_probe': :(.text+0x20224): undefined reference to `i2c_bit_add_bus' :(.text+0x20240): undefined reference to `i2c_del_adapter' make[2]: *** [vmlinux] Error 1 It's probably a good idea to mention that in the changeset text. Arnd