Date: Wed, 2 Jan 2019 12:10:09 +0100 From: =?UTF-8?B?VMSzbA==?= Coosemans <tijl@FreeBSD.org> To: Andrea Venturoli <ml@netfence.it> Cc: freebsd-x11@freebsd.org Subject: Re: Radeon HD 4250: screen going blank every few seconds Message-ID: <20190102121009.1e7dc313@kalimero.tijl.coosemans.org> In-Reply-To: <085ed1a6-c25f-807e-f8d5-d94b2a77ae4d@netfence.it> References: <4560f9e2-efcf-a1f5-728c-c26fcec34353@netfence.it> <20181230224607.1feb9cad@kalimero.tijl.coosemans.org> <20181230231814.4bf4cbff@kalimero.tijl.coosemans.org> <b4b173b0-c516-266a-703e-a7e3bdcb089e@netfence.it> <2cb2790f-4007-c1dc-3b49-e92e9810ee67@netfence.it> <20181231172237.55a1c19f@kalimero.tijl.coosemans.org> <085ed1a6-c25f-807e-f8d5-d94b2a77ae4d@netfence.it>
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On Mon, 31 Dec 2018 18:36:46 +0100 Andrea Venturoli <ml@netfence.it> wrote: > On 12/31/18 5:22 PM, T=C4=B3l Coosemans wrote: >> Software i2c needs this patch: >> https://github.com/FreeBSDDesktop/kms-drm/commit/6a3d6e69ab5bf47756fde2a= 7c00e3f7d6295c10f.patch >>=20 >> Save it as graphics/drm-fbsd11.2-kmod/files/patch-i2c and delete "a/" >> and "b/" from the file. Then rebuild drm-fbsd11.2-kmod. =20 >=20 > Thanks. > I'll try this patch if what I've already done does not solve (see my=20 > other message). >=20 > I like to understand what I'm doing, if possible, though; do you have=20 > some pointers of what this I2C is (WRT to x.org), what it does, etc...? It's a simple 2 wire bus used between components on a graphics card: https://en.wikipedia.org/wiki/I2C When hw_i2c is 0 the driver manages the I2C bus, when it's 1 the hardware manages it. The hardware implementation is often buggy, which is why hw_i2c should default to 0. It was set to 1 on FreeBSD because of a bug in the driver (fixed by the patch above). This only affects drm-fbsd11.2-kmod.
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