Re: [PATCH] staging: fbtft: fix unaligned vmem writes when txbuf is byte-offset

Andy Shevchenko <[email protected]>
Newsgroups org.kernel.vger.linux-fbdev,dev.linux.lists.linux-staging,org.freedesktop.lists.dri-devel,org.kernel.vger.linux-kernel
Organization Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo
Message-ID <[email protected]>
On Thu, Jun 25, 2026 at 07:02:37PM +0800, suryasaimadhu wrote:
> fbtft_write_vmem16_bus8() and fb_ra8875's write_vmem16_bus8() offset
> txbuf16 by one byte for a command/start prefix, then store 16-bit pixel
> data via txbuf16[i]. On strict-alignment architectures this can fault
> the same way as the write_reg path fixed in the previous patch.

.write_reg()

Can you provide a real world example of the failure?

> Use put_unaligned() for these stores.

Sounds like a fix without Fixes tag.

> Signed-off-by: suryasaimadhu <[email protected]>

Use your name in accordance with your official documents.

...

> +++ b/drivers/staging/fbtft/fb_ra8875.c
> @@ -10,6 +10,7 @@
>  #include <linux/delay.h>

>  

You should move this blank line to be...

>  #include <linux/gpio/consumer.h>
> +#include <linux/unaligned.h>

...here.

>  #include "fbtft.h"

...

>  #define DRVNAME "fb_ra8875"

Are other drivers also being affected?

...

> +++ b/drivers/staging/fbtft/fbtft-bus.c

Also needs linux/unaligned.h.

> +			put_unaligned(cpu_to_be16(vmem16[i]), &txbuf16[i]);

-- 
With Best Regards,
Andy Shevchenko
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.