From: Rob Clark <robdclark@gmail.com> To: Akhil P Oommen <akhilpo@codeaurora.org> Cc: Jonathan Marek <jonathan@marek.ca>, freedreno <freedreno@lists.freedesktop.org>, Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>, Eric Anholt <eric@anholt.net>, Sharat Masetty <smasetty@codeaurora.org>, "open list:DRM DRIVER FOR MSM ADRENO GPU" <linux-arm-msm@vger.kernel.org>, "open list:DRM DRIVER FOR MSM ADRENO GPU" <dri-devel@lists.freedesktop.org>, open list <linux-kernel@vger.kernel.org> Subject: Re: [PATCH] drm/msm/a6xx: fix for kernels without CONFIG_NVMEM Date: Thu, 18 Feb 2021 08:11:27 -0800 [thread overview] Message-ID: <CAF6AEGsWCrkOgMVxnx53k8b_o7xy3KWv9VaNRoY44+4GfXtWdg@mail.gmail.com> (raw) In-Reply-To: <e4b62857-bd4d-cca6-0d6b-b9cc960b52a2@codeaurora.org> 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 > > >> available, that isn't the end of the world. But if it makes things > >> not-work, that is sub-optimal. Generally, especially on ARM, kconfig > >> seems to be way harder than it should be to build a kernel that works, > >> if we could somehow not add to that problem (for both people with a6xx > >> and older gens) that would be nice ;-) > >> > > > > There is a "imply" kconfig option which solves exactly this problem. > > (you would "imply NVMEM" instead of "select NVMEM". then it would be > > possible to disable NVMEM but it would get enabled by default) > > > >> BR, > >> -R > >> > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel >
WARNING: multiple messages have this Message-ID (diff)
From: Rob Clark <robdclark@gmail.com> To: Akhil P Oommen <akhilpo@codeaurora.org> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>, Jonathan Marek <jonathan@marek.ca>, David Airlie <airlied@linux.ie>, freedreno <freedreno@lists.freedesktop.org>, Sharat Masetty <smasetty@codeaurora.org>, open list <linux-kernel@vger.kernel.org>, "open list:DRM DRIVER FOR MSM ADRENO GPU" <dri-devel@lists.freedesktop.org>, "open list:DRM DRIVER FOR MSM ADRENO GPU" <linux-arm-msm@vger.kernel.org>, Sean Paul <sean@poorly.run> Subject: Re: [PATCH] drm/msm/a6xx: fix for kernels without CONFIG_NVMEM Date: Thu, 18 Feb 2021 08:11:27 -0800 [thread overview] Message-ID: <CAF6AEGsWCrkOgMVxnx53k8b_o7xy3KWv9VaNRoY44+4GfXtWdg@mail.gmail.com> (raw) In-Reply-To: <e4b62857-bd4d-cca6-0d6b-b9cc960b52a2@codeaurora.org> 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 > > >> available, that isn't the end of the world. But if it makes things > >> not-work, that is sub-optimal. Generally, especially on ARM, kconfig > >> seems to be way harder than it should be to build a kernel that works, > >> if we could somehow not add to that problem (for both people with a6xx > >> and older gens) that would be nice ;-) > >> > > > > There is a "imply" kconfig option which solves exactly this problem. > > (you would "imply NVMEM" instead of "select NVMEM". then it would be > > possible to disable NVMEM but it would get enabled by default) > > > >> BR, > >> -R > >> > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2021-02-18 17:48 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-16 20:09 [PATCH] drm/msm/a6xx: fix for kernels without CONFIG_NVMEM Jonathan Marek 2021-02-16 20:09 ` Jonathan Marek 2021-02-17 3:06 ` Rob Clark 2021-02-17 3:06 ` Rob Clark 2021-02-17 13:44 ` Akhil P Oommen 2021-02-17 13:44 ` Akhil P Oommen 2021-02-17 19:08 ` Jordan Crouse 2021-02-17 19:08 ` Jordan Crouse 2021-02-17 20:18 ` Rob Clark 2021-02-17 20:18 ` Rob Clark 2021-02-17 20:35 ` Jonathan Marek 2021-02-17 20:35 ` Jonathan Marek 2021-02-18 12:28 ` Akhil P Oommen 2021-02-18 12:28 ` Akhil P Oommen 2021-02-18 16:11 ` Rob Clark [this message] 2021-02-18 16:11 ` Rob Clark 2021-02-19 10:44 ` Akhil P Oommen 2021-02-19 10:44 ` Akhil P Oommen 2021-02-19 16:00 ` Rob Clark 2021-02-19 16:00 ` Rob Clark 2021-02-22 15:45 ` Akhil P Oommen 2021-02-22 15:45 ` Akhil P Oommen 2021-02-22 16:06 ` Rob Clark 2021-02-22 16:06 ` Rob Clark 2021-04-01 20:12 ` Rob Clark 2021-04-01 20:12 ` Rob Clark 2021-04-01 21:03 ` Dmitry Baryshkov 2021-04-01 21:03 ` Dmitry Baryshkov 2021-04-01 21:49 ` Rob Clark 2021-04-01 21:49 ` Rob Clark 2021-04-03 4:39 ` Akhil P Oommen 2021-04-03 4:39 ` Akhil P Oommen
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