Re: [PATCH] drm/mgag200: Fix PLL setup for G200_SE_A rev >=4

From: Greg KH <gregkh@linuxfoundation.org>
To: Jocelyn Falempe <jfalempe@redhat.com>
Cc: stable@vger.kernel.org, Thomas Zimmermann <tzimmermann@suse.de>
Subject: Re: [PATCH] drm/mgag200: Fix PLL setup for G200_SE_A rev >=4
Date: Tue, 10 Jan 2023 18:30:56 +0100	[thread overview]
Message-ID: <Y72g0M2uHdcrG3E3@kroah.com> (raw)
In-Reply-To: <20230104162729.424575-1-jfalempe@redhat.com>

On Wed, Jan 04, 2023 at 05:27:29PM +0100, Jocelyn Falempe wrote:
> commit b389286d0234e1edbaf62ed8bc0892a568c33662 upstream.
> 
> For G200_SE_A, PLL M setting is wrong, which leads to blank screen,
> or "signal out of range" on VGA display.
> previous code had "m |= 0x80" which was changed to
> m |= ((pixpllcn & BIT(8)) >> 1);
> 
> Tested on G200_SE_A rev 42
> 
> This line of code was moved to another file with
> commit 877507bb954e ("drm/mgag200: Provide per-device callbacks for
> PIXPLLC") but can be easily backported before this commit.
> 
> v2: * put BIT(7) First to respect MSB-to-LSB (Thomas)
>     * Add a comment to explain that this bit must be set (Thomas)
> 
> backported to v6.0.17, it also applies cleanly to v5.15.86
> 
> Fixes: 2dd040946ecf ("drm/mgag200: Store values (not bits) in struct mgag200_pll_values")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
> Link: https://patchwork.freedesktop.org/patch/msgid/20221013132810.521945-1-jfalempe@redhat.com
> ---
>  drivers/gpu/drm/mgag200/mgag200_pll.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 

Now queued up, thanks.

greg k-h