From: Thomas Zimmermann <tzimmermann@suse.de>
To: Gerd Hoffmann <kraxel@redhat.com>, Nirmoy Das <nirmoy.aiemd@gmail.com>
Cc: thellstrom@vmware.com, airlied@linux.ie, kenny.ho@amd.com,
brian.welty@intel.com, dri-devel@lists.freedesktop.org,
nirmoy.das@amd.com, linux-graphics-maintainer@vmware.com,
amd-gfx@lists.freedesktop.org,
Daniel Vetter <daniel.vetter@ffwll.ch>,
alexander.deucher@amd.com, sean@poorly.run,
christian.koenig@amd.com, bskeggs@redhat.com
Subject: Re: [PATCH 6/8] drm/vram-helper: don't use ttm bo->offset v3
Date: Thu, 5 Mar 2020 15:26:05 +0100 [thread overview]
Message-ID: <6d7146b9-4ac1-e861-334f-950de790321d@suse.de> (raw)
In-Reply-To: <20200305140749.5oggp4gh6hozsh7j@sirius.home.kraxel.org>
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Hi
Am 05.03.20 um 15:07 schrieb Gerd Hoffmann:
> On Thu, Mar 05, 2020 at 02:29:08PM +0100, Nirmoy Das wrote:
>> Calculate GEM VRAM bo's offset within vram-helper without depending on
>> bo->offset.
>>
>> Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
>> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>> ---
>> drivers/gpu/drm/drm_gem_vram_helper.c | 9 ++++++++-
>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
>> index 92a11bb42365..2749c2d25ac4 100644
>> --- a/drivers/gpu/drm/drm_gem_vram_helper.c
>> +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
>> @@ -198,6 +198,13 @@ u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo)
>> }
>> EXPORT_SYMBOL(drm_gem_vram_mmap_offset);
>>
>> +static s64 drm_gem_vram_pg_offset(struct drm_gem_vram_object *gbo)
>> +{
>> + if (WARN_ON_ONCE(!gbo->bo.mem.mm_node))
>> + return 0;
>
> returns 0 on error.
>
>> + return gbo->bo.mem.start;
>> +}
>> +
>> /**
>> * drm_gem_vram_offset() - \
>> Returns a GEM VRAM object's offset in video memory
>> @@ -214,7 +221,7 @@ s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo)
>> {
>> if (WARN_ON_ONCE(!gbo->pin_count))
>> return (s64)-ENODEV;
>
> returns -errno on error.
>
>> - return gbo->bo.offset;
>> + return drm_gem_vram_pg_offset(gbo) << PAGE_SHIFT;
>
> And given that one calls the other behavior on error should better be
> consistent ...
It is expected that the offset is valid if pin_count is positive.
Anything else would be a massive ref-counting bug. And that's been the
behavior of the old code as well.
But I agree that the current patch is inconsistent. I suggest changing
the return type of drm_gem_vram_pg_offset() to u64.
Best regards
Thomas
>
> cheers,
> Gerd
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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next prev parent reply other threads:[~2020-03-05 14:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-05 13:29 [PATCH v4 0/8] do not store GPU address in TTM Nirmoy Das
2020-03-05 13:29 ` [PATCH 1/8] drm/amdgpu: move ttm bo->offset to amdgpu_bo Nirmoy Das
2020-03-05 19:11 ` Luben Tuikov
2020-03-05 13:29 ` [PATCH 2/8] drm/radeon: don't use ttm bo->offset Nirmoy Das
2020-03-05 19:19 ` Luben Tuikov
2020-03-05 19:37 ` Ho, Kenny
2020-03-05 20:18 ` Luben Tuikov
2020-03-05 13:29 ` [PATCH 3/8] drm/vmwgfx: " Nirmoy Das
2020-03-05 13:29 ` [PATCH 4/8] drm/nouveau: don't use ttm bo->offset v3 Nirmoy Das
2020-03-05 13:33 ` Christian König
2020-03-05 19:23 ` Luben Tuikov
2020-03-05 13:29 ` [PATCH 5/8] drm/qxl: don't use ttm bo->offset Nirmoy Das
2020-03-05 13:29 ` [PATCH 6/8] drm/vram-helper: don't use ttm bo->offset v3 Nirmoy Das
2020-03-05 14:07 ` Gerd Hoffmann
2020-03-05 14:26 ` Thomas Zimmermann [this message]
2020-03-05 14:35 ` Nirmoy
2020-03-05 14:34 ` Christian König
2020-03-05 13:29 ` [PATCH 7/8] drm/bochs: use drm_gem_vram_offset to get bo offset v2 Nirmoy Das
2020-03-05 13:29 ` [PATCH 8/8] drm/ttm: do not keep GPU dependent addresses Nirmoy Das
2020-03-05 13:34 ` Christian König
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