From: Christoph Hellwig <hch@lst.de>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>,
linux-mips@vger.kernel.org, linux-fbdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] au1200fb: don't use DMA_ATTR_NON_CONSISTENT
Date: Tue, 25 Jun 2019 14:13:21 +0200 [thread overview]
Message-ID: <20190625121321.10197-1-hch@lst.de> (raw)
au1200fb allocates DMA memory using DMA_ATTR_NON_CONSISTENT, but never
calls dma_cache_sync to synchronize the memory between the CPU and the
device. If it was use on a not cache coherent bus that would be fatal,
but as far as I can tell from the naming and the mips platform
implementation it always is used in cache coherent systems. Remove
the DMA_ATTR_NON_CONSISTENT flag, which is a no-op in that case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/video/fbdev/au1200fb.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/video/fbdev/au1200fb.c b/drivers/video/fbdev/au1200fb.c
index 26caffb02b7e..265d3b45efd0 100644
--- a/drivers/video/fbdev/au1200fb.c
+++ b/drivers/video/fbdev/au1200fb.c
@@ -1234,7 +1234,7 @@ static int au1200fb_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
struct au1200fb_device *fbdev = info->par;
return dma_mmap_attrs(fbdev->dev, vma, fbdev->fb_mem, fbdev->fb_phys,
- fbdev->fb_len, DMA_ATTR_NON_CONSISTENT);
+ fbdev->fb_len, 0);
}
static void set_global(u_int cmd, struct au1200_lcd_global_regs_t *pdata)
@@ -1692,8 +1692,7 @@ static int au1200fb_drv_probe(struct platform_device *dev)
fbdev->fb_mem = dmam_alloc_attrs(&dev->dev,
PAGE_ALIGN(fbdev->fb_len),
- &fbdev->fb_phys, GFP_KERNEL,
- DMA_ATTR_NON_CONSISTENT);
+ &fbdev->fb_phys, GFP_KERNEL, 0);
if (!fbdev->fb_mem) {
print_err("fail to allocate framebuffer (size: %dK))",
fbdev->fb_len / 1024);
--
2.20.1
next reply other threads:[~2019-06-25 12:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 12:13 Christoph Hellwig [this message]
2019-06-26 7:16 ` [PATCH] au1200fb: don't use DMA_ATTR_NON_CONSISTENT Manuel Lauss
2019-07-23 15:35 ` Bartlomiej Zolnierkiewicz
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