Messages in this thread | | | Subject | Re: [PATCH] drm/msm/a6xx: fix for kernels without CONFIG_NVMEM | From | Akhil P Oommen <> | Date | Sat, 3 Apr 2021 10:09:49 +0530 |
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On 4/2/2021 3:19 AM, Rob Clark wrote: > On Thu, Apr 1, 2021 at 2:03 PM Dmitry Baryshkov > <dmitry.baryshkov@linaro.org> wrote: >> >> On Thu, 1 Apr 2021 at 23:09, Rob Clark <robdclark@gmail.com> wrote: >>> >>> On Mon, Feb 22, 2021 at 8:06 AM Rob Clark <robdclark@gmail.com> wrote: >>>> >>>> On Mon, Feb 22, 2021 at 7:45 AM Akhil P Oommen <akhilpo@codeaurora.org> wrote: >>>>> >>>>> On 2/19/2021 9:30 PM, Rob Clark wrote: >>>>>> On Fri, Feb 19, 2021 at 2:44 AM Akhil P Oommen <akhilpo@codeaurora.org> wrote: >>>>>>> >>>>>>> On 2/18/2021 9:41 PM, Rob Clark wrote: >>>>>>>> On Thu, Feb 18, 2021 at 4:28 AM Akhil P Oommen <akhilpo@codeaurora.org> wrote: >>>>>>>>> >>>>>>>>> On 2/18/2021 2:05 AM, Jonathan Marek wrote: >>>>>>>>>> On 2/17/21 3:18 PM, Rob Clark wrote: >>>>>>>>>>> On Wed, Feb 17, 2021 at 11:08 AM Jordan Crouse >>>>>>>>>>> <jcrouse@codeaurora.org> wrote: >>>>>>>>>>>> >>>>>>>>>>>> On Wed, Feb 17, 2021 at 07:14:16PM +0530, Akhil P Oommen wrote: >>>>>>>>>>>>> On 2/17/2021 8:36 AM, Rob Clark wrote: >>>>>>>>>>>>>> On Tue, Feb 16, 2021 at 12:10 PM Jonathan Marek <jonathan@marek.ca> >>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Ignore nvmem_cell_get() EOPNOTSUPP error in the same way as a >>>>>>>>>>>>>>> ENOENT error, >>>>>>>>>>>>>>> to fix the case where the kernel was compiled without CONFIG_NVMEM. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Fixes: fe7952c629da ("drm/msm: Add speed-bin support to a618 gpu") >>>>>>>>>>>>>>> Signed-off-by: Jonathan Marek <jonathan@marek.ca> >>>>>>>>>>>>>>> --- >>>>>>>>>>>>>>> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 6 +++--- >>>>>>>>>>>>>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >>>>>>>>>>>>>>> b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >>>>>>>>>>>>>>> index ba8e9d3cf0fe..7fe5d97606aa 100644 >>>>>>>>>>>>>>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >>>>>>>>>>>>>>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >>>>>>>>>>>>>>> @@ -1356,10 +1356,10 @@ static int a6xx_set_supported_hw(struct >>>>>>>>>>>>>>> device *dev, struct a6xx_gpu *a6xx_gpu, >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> cell = nvmem_cell_get(dev, "speed_bin"); >>>>>>>>>>>>>>> /* >>>>>>>>>>>>>>> - * -ENOENT means that the platform doesn't support >>>>>>>>>>>>>>> speedbin which is >>>>>>>>>>>>>>> - * fine >>>>>>>>>>>>>>> + * -ENOENT means no speed bin in device tree, >>>>>>>>>>>>>>> + * -EOPNOTSUPP means kernel was built without CONFIG_NVMEM >>>>>>>>>>>>>> >>>>>>>>>>>>>> very minor nit, it would be nice to at least preserve the gist of the >>>>>>>>>>>>>> "which is fine" (ie. some variation of "this is an optional thing and >>>>>>>>>>>>>> things won't catch fire without it" ;-)) >>>>>>>>>>>>>> >>>>>>>>>>>>>> (which is, I believe, is true, hopefully Akhil could confirm.. if not >>>>>>>>>>>>>> we should have a harder dependency on CONFIG_NVMEM..) >>>>>>>>>>>>> IIRC, if the gpu opp table in the DT uses the 'opp-supported-hw' >>>>>>>>>>>>> property, >>>>>>>>>>>>> we will see some error during boot up if we don't call >>>>>>>>>>>>> dev_pm_opp_set_supported_hw(). So calling "nvmem_cell_get(dev, >>>>>>>>>>>>> "speed_bin")" >>>>>>>>>>>>> is a way to test this. >>>>>>>>>>>>> >>>>>>>>>>>>> If there is no other harm, we can put a hard dependency on >>>>>>>>>>>>> CONFIG_NVMEM. >>>>>>>>>>>> >>>>>>>>>>>> I'm not sure if we want to go this far given the squishiness about >>>>>>>>>>>> module >>>>>>>>>>>> dependencies. As far as I know we are the only driver that uses this >>>>>>>>>>>> seriously >>>>>>>>>>>> on QCOM SoCs and this is only needed for certain targets. I don't >>>>>>>>>>>> know if we >>>>>>>>>>>> want to force every target to build NVMEM and QFPROM on our behalf. >>>>>>>>>>>> But maybe >>>>>>>>>>>> I'm just saying that because Kconfig dependencies tend to break my >>>>>>>>>>>> brain (and >>>>>>>>>>>> then Arnd has to send a patch to fix it). >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Hmm, good point.. looks like CONFIG_NVMEM itself doesn't have any >>>>>>>>>>> other dependencies, so I suppose it wouldn't be the end of the world >>>>>>>>>>> to select that.. but I guess we don't want to require QFPROM >>>>>>>>>>> >>>>>>>>>>> I guess at the end of the day, what is the failure mode if you have a >>>>>>>>>>> speed-bin device, but your kernel config misses QFPROM (and possibly >>>>>>>>>>> NVMEM)? If the result is just not having the highest clk rate(s) >>>>>>>>> >>>>>>>>> Atleast on sc7180's gpu, using an unsupported FMAX breaks gmu. It won't >>>>>>>>> be very obvious what went wrong when this happens! >>>>>>>> >>>>>>>> Ugg, ok.. >>>>>>>> >>>>>>>> I suppose we could select NVMEM, but not QFPROM, and then the case >>>>>>>> where QFPROM is not enabled on platforms that have the speed-bin field >>>>>>>> in DT will fail gracefully and all other platforms would continue on >>>>>>>> happily? >>>>>>>> >>>>>>>> BR, >>>>>>>> -R >>>>>>> >>>>>>> Sounds good to me. >>>>>>> >>>>>> >>>>>> You probably should do a quick test with NVMEM enabled but QFPROM >>>>>> disabled to confirm my theory, but I *think* that should work >>>>>> >>>>>> BR, >>>>>> -R >>>>>> >>>>> >>>>> I tried it on an sc7180 device. The suggested combo (CONFIG_NVMEM + no >>>>> CONFIG_QCOM_QFPROM) makes the gpu probe fail with error "failed to read >>>>> speed-bin. Some OPPs may not be supported by hardware". This is good >>>>> enough clue for the developer that he should fix the broken speedbin >>>>> detection. >>>>> >>>> >>>> Ok, great.. then sounds like selecting NVMEM is a good approach >>>> >>> >>> btw, did anyone ever send a patch to select NVMEM? I'm not seeing one >>> but I could be overlooking something I thought Jonathan would send it as the discussion was going on in his patch. No problem, I will send it out. :)
-Akhil.
>> >> Judging by the amount of issues surrounding speed-bin, I might have a >> bold suggestion to revert these patches for now and get them once all >> the issues are sorted, so that we'd have a single working commit >> instead of scattered patch series breaking git bisect, having bad >> side-effects on non-sc7180 platforms, etc. >> > > We do really need some pre-merge CI like we have on the mesa side of > things (and we at least have 845 devices in our CI farm, but it would > be useful to add more generations).. but other than the config issue, > I *think* this fixes the last of the speedbin fallout? > > https://patchwork.freedesktop.org/patch/426538/?series=88558&rev=1 > > Planning to include that in a -fixes pull req in the next day or two. > (And please have a look at msm-next-staging and let me know if you see > anything other fixes that would be good to get in, speedbin related or > otherwise.) > > BR, > -R > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel >
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