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From 8c9d9211e241b97fa67d130436e7346bba28aeec Mon Sep 17 00:00:00 2001
From: Roman Kapl <rka@sysgo.com>
Date: Mon, 30 Oct 2017 11:56:13 +0100
Subject: [PATCH 2095/4131] drm/radeon: fix atombios on big endian
The function for byteswapping the data send to/from atombios was buggy for
num_bytes not divisible by four. The function must be aware of the fact
that after byte-swapping the u32 units, valid bytes might end up after the
num_bytes boundary.
This patch was tested on kernel 3.12 and allowed us to sucesfully use
DisplayPort on and Radeon SI card. Namely it fixed the link training and
EDID readout.
The function is patched both in radeon and amd drivers, since the functions
and the fixes are identical.
Signed-off-by: Roman Kapl <rka@sysgo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
---
drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
index 31a96a3..1f32110 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
@@ -1778,26 +1778,20 @@ bool amdgpu_atombios_scratch_need_asic_init(struct amdgpu_device *adev)
void amdgpu_atombios_copy_swap(u8 *dst, u8 *src, u8 num_bytes, bool to_le)
{
#ifdef __BIG_ENDIAN
- u8 src_tmp[20], dst_tmp[20]; /* used for byteswapping */
- u32 *dst32, *src32;
+ u32 src_tmp[5], dst_tmp[5];
int i;
+ u8 align_num_bytes = ALIGN(num_bytes, 4);
- memcpy(src_tmp, src, num_bytes);
- src32 = (u32 *)src_tmp;
- dst32 = (u32 *)dst_tmp;
if (to_le) {
- for (i = 0; i < ((num_bytes + 3) / 4); i++)
- dst32[i] = cpu_to_le32(src32[i]);
- memcpy(dst, dst_tmp, num_bytes);
+ memcpy(src_tmp, src, num_bytes);
+ for (i = 0; i < align_num_bytes / 4; i++)
+ dst_tmp[i] = cpu_to_le32(src_tmp[i]);
+ memcpy(dst, dst_tmp, align_num_bytes);
} else {
- u8 dws = num_bytes & ~3;
- for (i = 0; i < ((num_bytes + 3) / 4); i++)
- dst32[i] = le32_to_cpu(src32[i]);
- memcpy(dst, dst_tmp, dws);
- if (num_bytes % 4) {
- for (i = 0; i < (num_bytes % 4); i++)
- dst[dws+i] = dst_tmp[dws+i];
- }
+ memcpy(src_tmp, src, align_num_bytes);
+ for (i = 0; i < align_num_bytes / 4; i++)
+ dst_tmp[i] = le32_to_cpu(src_tmp[i]);
+ memcpy(dst, dst_tmp, num_bytes);
}
#else
memcpy(dst, src, num_bytes);
--
2.7.4
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