From: Marek Szyprowski <m.szyprowski@samsung.com>
To: "Christian König" <christian.koenig@amd.com>,
"Shane Francis" <bigbeeshane@gmail.com>,
dri-devel@lists.freedesktop.org
Cc: airlied@linux.ie, linux-kernel@vger.kernel.org,
amd-gfx-request@lists.freedesktop.org, alexander.deucher@amd.com
Subject: Re: [v4,1/3] drm/prime: use dma length macro when mapping sg
Date: Mon, 30 Mar 2020 10:18:21 +0200 [thread overview]
Message-ID: <bba81019-d585-d950-ecd0-c0bf36a2f58d@samsung.com> (raw)
In-Reply-To: <cd773011-969b-28df-7488-9fddae420d81@samsung.com>
Hi
On 2020-03-27 10:10, Marek Szyprowski wrote:
> Hi Christian,
>
> On 2020-03-27 09:11, Christian König wrote:
>> Am 27.03.20 um 08:54 schrieb Marek Szyprowski:
>>> On 2020-03-25 10:07, Shane Francis wrote:
>>>> As dma_map_sg can reorganize scatter-gather lists in a
>>>> way that can cause some later segments to be empty we should
>>>> always use the sg_dma_len macro to fetch the actual length.
>>>>
>>>> This could now be 0 and not need to be mapped to a page or
>>>> address array
>>>>
>>>> Signed-off-by: Shane Francis <bigbeeshane@gmail.com>
>>>> Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
>>> This patch landed in linux-next 20200326 and it causes a kernel
>>> panic on
>>> various Exynos SoC based boards.
>>>> ---
>>>> drivers/gpu/drm/drm_prime.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
>>>> index 86d9b0e45c8c..1de2cde2277c 100644
>>>> --- a/drivers/gpu/drm/drm_prime.c
>>>> +++ b/drivers/gpu/drm/drm_prime.c
>>>> @@ -967,7 +967,7 @@ int drm_prime_sg_to_page_addr_arrays(struct
>>>> sg_table *sgt, struct page **pages,
>>>> index = 0;
>>>> for_each_sg(sgt->sgl, sg, sgt->nents, count) {
>>>> - len = sg->length;
>>>> + len = sg_dma_len(sg);
>>>> page = sg_page(sg);
>>>> addr = sg_dma_address(sg);
>>> Sorry, but this code is wrong :(
>>
>> Well it is at least better than before because it makes most drivers
>> work correctly again.
>
> Well, I'm not sure that a half-broken fix should be considered as a
> fix ;)
>
> Anyway, I just got the comment from Shane, that my patch is fixing the
> issues with amdgpu and radeon, while still working fine for exynos, so
> it is indeed a proper fix.
Today I've noticed that this patch went to final v5.6 without even a day
of testing in linux-next, so v5.6 is broken on Exynos and probably a few
other ARM archs, which rely on the drm_prime_sg_to_page_addr_arrays
function.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2020-03-30 8:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 9:07 [PATCH v4 0/3] AMDGPU / RADEON / DRM Fix mapping of user pages Shane Francis
2020-03-25 9:07 ` [PATCH v4 1/3] drm/prime: use dma length macro when mapping sg Shane Francis
2020-03-25 13:56 ` Ruhl, Michael J
[not found] ` <CGME20200327075458eucas1p2f1011560c5d2d2a754d2394f56367ebb@eucas1p2.samsung.com>
2020-03-27 7:54 ` [v4,1/3] " Marek Szyprowski
2020-03-27 8:11 ` Christian König
2020-03-27 9:10 ` Marek Szyprowski
2020-03-30 8:18 ` Marek Szyprowski [this message]
2020-03-30 9:39 ` Shane Francis
2020-03-30 12:32 ` Shane Francis
2020-03-30 12:34 ` Shane Francis
2020-03-30 13:23 ` Alex Deucher
2020-03-31 5:25 ` Marek Szyprowski
2020-03-31 14:10 ` Alex Deucher
2020-03-31 14:29 ` Marek Szyprowski
[not found] ` <CGME20200327082702eucas1p1a66dd059480c9d02b8f0f3ab225db2c3@eucas1p1.samsung.com>
2020-03-27 8:26 ` Marek Szyprowski
2020-03-25 9:07 ` [PATCH v4 2/3] drm/amdgpu: fix scatter-gather mapping with user pages Shane Francis
2020-03-25 14:00 ` Ruhl, Michael J
2020-03-25 9:07 ` [PATCH v4 3/3] drm/radeon: " Shane Francis
2020-03-25 14:19 ` Ruhl, Michael J
2020-03-25 15:54 ` Shane Francis
2020-03-25 16:08 ` Alex Deucher
2020-03-25 13:11 ` [PATCH v4 0/3] AMDGPU / RADEON / DRM Fix mapping of " Ruhl, Michael J
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