FAILED: patch "[PATCH] drm/mgag200: Fix PLL setup for G200_SE_A rev >=4" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] drm/mgag200: Fix PLL setup for G200_SE_A rev >=4" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

Possible dependencies:

b389286d0234 ("drm/mgag200: Fix PLL setup for G200_SE_A rev >=4")
877507bb954e ("drm/mgag200: Provide per-device callbacks for PIXPLLC")
8aeeb3144fe2 ("drm/mgag200: Provide per-device callbacks for BMC synchronization")
f639f74a7895 ("drm/mgag200: Add per-device callbacks")
1baf9127c482 ("drm/mgag200: Replace simple-KMS with regular atomic helpers")
4f4dc37e374c ("drm/mgag200: Reorganize before dropping simple-KMS helpers")
ed2ef21f1089 ("drm/mgag200: Store primary plane's color format in CRTC state")
2d70b9a1482e ("drm/mgag200: Acquire I/O-register lock in atomic_commit_tail function")
1ee181fe958a ("drm/mgag200: Move DAC-register setup into model-specific code")
44373151ab42 ("drm/mgag200: Split mgag200_modeset_init()")
98da4b99a052 ("drm/mgag200: Store maximum resolution and memory bandwidth in device info")
21e74bf99596 ("drm/mgag200: Store HW_BUG_NO_STARTADD flag in device info")
b9a577a407d9 ("drm/mgag200: Add struct mgag200_device_info")
b62d943e9686 ("drm/mgag200: Implement new init logic")
d45e32c9d98c ("drm/mgag200: Call mgag200_device_probe_vram() from per-model init")
ce19021fd99a ("drm/mgag200: Move PCI-option setup into model-specific code")
85397f6bc4ff ("drm/mgag200: Initialize each model in separate function")
73f54d5d9682 ("drm/mgag200: Remove special case for G200SE with <2 MiB")
475e2b970cc3 ("drm/mgag200: Split up connector's mode_valid helper")
69340e529a06 ("drm/mgag200: Test memory requirements in drm_mode_config_funcs.mode_valid")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b389286d0234e1edbaf62ed8bc0892a568c33662 Mon Sep 17 00:00:00 2001
From: Jocelyn Falempe <jfalempe@redhat.com>
Date: Thu, 13 Oct 2022 15:28:10 +0200
Subject: [PATCH] drm/mgag200: Fix PLL setup for G200_SE_A rev >=4

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)

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

diff --git a/drivers/gpu/drm/mgag200/mgag200_g200se.c b/drivers/gpu/drm/mgag200/mgag200_g200se.c
index be389ed91cbd..bd6e573c9a1a 100644
--- a/drivers/gpu/drm/mgag200/mgag200_g200se.c
+++ b/drivers/gpu/drm/mgag200/mgag200_g200se.c
@@ -284,7 +284,8 @@ static void mgag200_g200se_04_pixpllc_atomic_update(struct drm_crtc *crtc,
 	pixpllcp = pixpllc->p - 1;
 	pixpllcs = pixpllc->s;
 
-	xpixpllcm = pixpllcm | ((pixpllcn & BIT(8)) >> 1);
+	// For G200SE A, BIT(7) should be set unconditionally.
+	xpixpllcm = BIT(7) | pixpllcm;
 	xpixpllcn = pixpllcn;
 	xpixpllcp = (pixpllcs << 3) | pixpllcp;