[PATCH] drm/amdgpu: Add sysfs file for VBIOS
Christian König
deathsimple at vodafone.de
Thu Aug 24 18:10:35 UTC 2017
Actually the main difference is not root vs. user, but rather unstable
vs stable interface.
If you want a stable interface for an userspace tool you should use
sysfs, if you don't care about that you should use debugfs.
Christian.
Am 24.08.2017 um 18:37 schrieb Russell, Kent:
> We already access the GPU Power usage via debugfs, which is why I didn't think it was a huge deal to switch it over, since we already need root access for the SMI due to that.
>
> Kent
>
> -----Original Message-----
> From: Alex Deucher [mailto:alexdeucher at gmail.com]
> Sent: Thursday, August 24, 2017 11:39 AM
> To: Kuehling, Felix
> Cc: Russell, Kent; Christian König; amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS
>
> On Thu, Aug 24, 2017 at 11:35 AM, Kuehling, Felix <Felix.Kuehling at amd.com> wrote:
>> Debugfs is only accessible by Root. The BIOS version is already reported in the kernel log, which is visible to everyone. So why hide this away in debugfs?
>>
>> I think Kent's intention is to add VBIOS version reporting to the rocm-smi tool. I'd prefer using a stable interface like sysfs, and one that doesn't require root access in a tool like rocm-smi.
>>
> Ah, ok, sysfs is fine in that case. I thought this was just general debugging stuff.
>
> Alex
>
>> Regards,
>> Felix
>> ________________________________________
>> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of
>> Russell, Kent <Kent.Russell at amd.com>
>> Sent: Thursday, August 24, 2017 9:06:22 AM
>> To: Alex Deucher
>> Cc: Christian König; amd-gfx at lists.freedesktop.org
>> Subject: RE: [PATCH] drm/amdgpu: Add sysfs file for VBIOS
>>
>> I can definitely add that as well.
>>
>> Kent
>>
>> -----Original Message-----
>> From: Alex Deucher [mailto:alexdeucher at gmail.com]
>> Sent: Thursday, August 24, 2017 8:56 AM
>> To: Russell, Kent
>> Cc: Christian König; amd-gfx at lists.freedesktop.org
>> Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS
>>
>> On Thu, Aug 24, 2017 at 5:58 AM, Russell, Kent <Kent.Russell at amd.com> wrote:
>>> No real reason for sysfs instead of debugfs, I just picked the one that was more familiar with. I can definitely move it to debugfs instead. I will also clean up the commit message per Michel's comments. Thank you!
>>>
>> While you are at it, can you expose the vbios binary itself via debugfs? That's been on by todo list for a while.
>>
>> Alex
>>
>>> Kent
>>>
>>> -----Original Message-----
>>> From: Christian König [mailto:deathsimple at vodafone.de]
>>> Sent: Thursday, August 24, 2017 2:22 AM
>>> To: Russell, Kent; amd-gfx at lists.freedesktop.org
>>> Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS
>>>
>>> Am 23.08.2017 um 20:12 schrieb Kent Russell:
>>>> This won't change after initialization, so we can add the
>>>> information when we parse the atombios information. This ensures
>>>> that we can find out the VBIOS, even when the dmesg buffer fills up,
>>>> and makes it easier to associate which VBIOS is for which GPU on
>>>> mGPU configurations. Set the size to 20 characters in case of some
>>>> weird VBIOS suffix that exceeds the expected 17 character format
>>>> (3-8-3\0)
>>> Is there any reason that needs to be sysfs? Sounds more like an use case for debugfs.
>>>
>>> Christian.
>>>
>>>> Signed-off-by: Kent Russell <kent.russell at amd.com>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 23 +++++++++++++++++++++++
>>>> drivers/gpu/drm/amd/amdgpu/atom.c | 5 ++++-
>>>> drivers/gpu/drm/amd/amdgpu/atom.h | 1 +
>>>> 3 files changed, 28 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>> index a1f9424..f40be71 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>> @@ -888,6 +888,20 @@ static uint32_t cail_ioreg_read(struct card_info *info, uint32_t reg)
>>>> return r;
>>>> }
>>>>
>>>> +static ssize_t amdgpu_atombios_get_vbios_version(struct device *dev,
>>>> + struct device_attribute *attr,
>>>> + char *buf) {
>>>> + struct drm_device *ddev = dev_get_drvdata(dev);
>>>> + struct amdgpu_device *adev = ddev->dev_private;
>>>> + struct atom_context *ctx = adev->mode_info.atom_context;
>>>> +
>>>> + return snprintf(buf, PAGE_SIZE, "%s\n", ctx->vbios_version); }
>>>> +
>>>> +static DEVICE_ATTR(vbios_version, 0444, amdgpu_atombios_get_vbios_version,
>>>> + NULL);
>>>> +
>>>> /**
>>>> * amdgpu_atombios_fini - free the driver info and callbacks for atombios
>>>> *
>>>> @@ -907,6 +921,7 @@ static void amdgpu_atombios_fini(struct amdgpu_device *adev)
>>>> adev->mode_info.atom_context = NULL;
>>>> kfree(adev->mode_info.atom_card_info);
>>>> adev->mode_info.atom_card_info = NULL;
>>>> + device_remove_file(adev->dev, &dev_attr_vbios_version);
>>>> }
>>>>
>>>> /**
>>>> @@ -923,6 +938,7 @@ static int amdgpu_atombios_init(struct amdgpu_device *adev)
>>>> {
>>>> struct card_info *atom_card_info =
>>>> kzalloc(sizeof(struct card_info), GFP_KERNEL);
>>>> + int ret;
>>>>
>>>> if (!atom_card_info)
>>>> return -ENOMEM;
>>>> @@ -959,6 +975,13 @@ static int amdgpu_atombios_init(struct amdgpu_device *adev)
>>>> amdgpu_atombios_scratch_regs_init(adev);
>>>> amdgpu_atombios_allocate_fb_scratch(adev);
>>>> }
>>>> +
>>>> + ret = device_create_file(adev->dev, &dev_attr_vbios_version);
>>>> + if (ret) {
>>>> + DRM_ERROR("Failed to create device file for VBIOS version\n");
>>>> + return ret;
>>>> + }
>>>> +
>>>> return 0;
>>>> }
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.c
>>>> b/drivers/gpu/drm/amd/amdgpu/atom.c
>>>> index d69aa2e..69500a8 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/atom.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/atom.c
>>>> @@ -1343,8 +1343,11 @@ struct atom_context *amdgpu_atom_parse(struct card_info *card, void *bios)
>>>> idx = 0x80;
>>>>
>>>> str = CSTR(idx);
>>>> - if (*str != '\0')
>>>> + if (*str != '\0') {
>>>> pr_info("ATOM BIOS: %s\n", str);
>>>> + strlcpy(ctx->vbios_version, str, sizeof(ctx->vbios_version));
>>>> + }
>>>> +
>>>>
>>>> return ctx;
>>>> }
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.h
>>>> b/drivers/gpu/drm/amd/amdgpu/atom.h
>>>> index ddd8045..a391709 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/atom.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/atom.h
>>>> @@ -140,6 +140,7 @@ struct atom_context {
>>>> int io_mode;
>>>> uint32_t *scratch;
>>>> int scratch_size_bytes;
>>>> + char vbios_version[20];
>>>> };
>>>>
>>>> extern int amdgpu_atom_debug;
>>>
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