On 17-04-10 09:39 PM, Michel Dänzer wrote: > On 11/04/17 03:13 AM, Felix Kuehling wrote: >> On 17-04-09 09:28 PM, Michel Dänzer wrote: >>> On 10/04/17 09:56 AM, Michel Dänzer wrote: >>>> On 08/04/17 05:15 AM, Felix Kuehling wrote: >>>>> Advertise CIK PCI IDs only when they are not supported by amdgpu. >>>>> Use the CONFIG_DRM_AMDGPU_CIK to check so that a single option in >>>>> the kernel config keeps both drivers in sync. >>>>> >>>>> This is the simplest possible change. A more complete solution >>>>> may want to conditionally disable more CIK-specific code in the >>>>> Radeon driver. >>>>> >>>>> v2: Add CONFIG_DRM_RADEON_FORCE_CIK option >>>>> >>>>> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com> >>>> I don't think this is good enough a solution. >>> To elaborate, my main objection is that people who still want to be able >>> to use the radeon driver for CIK/SI GPUs with CONFIG_DRM_AMDGPU_CIK >>> enabled have to enable the new CONFIG_DRM_RADEON_FORCE_CIK/SI option, >>> and then they're merely back to square one, in the current situation >>> where it's not clearly defined which driver will end up being used for >>> such GPUs. >> So what's the usage model here? I think the situation that both AMDGPU >> and Radeon support CIK is for developers only. "Normal end users" would >> never be in this situation. > I agree in the long term, but for now, there's still too many bugs which > force users to use one or the other driver. Since this patch would > require distros to choose one driver for all of their users, with no way > to override at runtime, it would probably result in bad user experiences > and/or a support nightmare at least in the short term. Right now the only sane configuration that a distro can choose is to support CIK with radeon and not build CIK support into amdgpu. That choice will still be available. So nothing changes for a risk-averse distribution. If a distribution's choice does not work for all users, and end users have to change the preference at runtime, that's already a bad user experience. Just having the runtime option available doesn't make it a better user experience, because most user won't know that there is a choice and won't know that their issues can be fixed that way. Regards, Felix
