All of lore.kernel.org
 help / color / mirror / Atom feed
From: Luca Casati <luk00casati@gmail.com>
To: linux-wireless@vger.kernel.org
Cc: johannes@sipsolutions.net, arend.vanspriel@broadcom.com,
	b43-dev@lists.infradead.org, Luca Casati <luk00casati@gmail.com>
Subject: [PATCH wireless-next 3/5] b43: N-PHY: fix rev3+ RSSI calibration
Date: Mon, 26 Oct 2026 19:15:41 +0100	[thread overview]
Message-ID: <20261026181543.77763-4-luk00casati@gmail.com> (raw)
In-Reply-To: <20261026181543.77763-1-luk00casati@gmail.com>

Three bugs in b43_nphy_rev3_rssi_cal():

- On rev7+ the selected VCM was written using the loop counter (8 after
  the search loop) instead of vcm_final; the 3-bit field turned that
  into VCM 0 on every rev7+ PHY.
- The distance used I*I + Q*I instead of I*I + Q*Q (brcmsmac
  wlc_phy_rssi_cal_nphy_rev3()).
- Negative W1/W2 offsets were rounded as -(abs(x + 4) / 8) instead of
  -((abs(x) + 4) / 8).

Found and fixed with the help of an AI coding assistant (Claude Opus 5.5),
by comparing mmiotraces of b43 and wl on the same card.

Signed-off-by: Luca Casati <luk00casati@gmail.com>
---
 drivers/net/wireless/broadcom/b43/phy_n.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c
index cabf61870..44769dbb7 100644
--- a/drivers/net/wireless/broadcom/b43/phy_n.c
+++ b/drivers/net/wireless/broadcom/b43/phy_n.c
@@ -2167,7 +2167,7 @@ static void b43_nphy_rev3_rssi_cal(struct b43_wldev *dev)
 				continue;
 			for (vcm = 0; vcm < 8; vcm++) {
 				currd = results[vcm][i] * results[vcm][i] +
-					results[vcm][i + 1] * results[vcm][i];
+					results[vcm][i + 1] * results[vcm][i + 1];
 				if (currd < mind) {
 					mind = currd;
 					minvcm = vcm;
@@ -2179,12 +2179,16 @@ static void b43_nphy_rev3_rssi_cal(struct b43_wldev *dev)
 			results_min[i] = minpoll;
 		}
 
-		/* Select the best VCM */
+		/*
+		 * Select the best VCM. (This used to write the loop counter,
+		 * 8, which the 3-bit field turned into VCM 0 on every rev7+
+		 * PHY.)
+		 */
 		if (dev->phy.rev >= 7)
 			b43_radio_maskset(dev,
 					  core ? R2057_NB_MASTER_CORE1 :
 						 R2057_NB_MASTER_CORE0,
-					  ~R2057_VCM_MASK, vcm);
+					  ~R2057_VCM_MASK, vcm_final);
 		else
 			b43_radio_maskset(dev, r | B2056_RX_RSSI_MISC,
 					  0xE3, vcm_final << 2);
@@ -2219,7 +2223,7 @@ static void b43_nphy_rev3_rssi_cal(struct b43_wldev *dev)
 				if (j / 2 == core) {
 					offset[j] = 232 - poll_results[j];
 					if (offset[j] < 0)
-						offset[j] = -(abs(offset[j] + 4) / 8);
+						offset[j] = -((abs(offset[j]) + 4) / 8);
 					else
 						offset[j] = (offset[j] + 4) / 8;
 					b43_nphy_scale_offset_rssi(dev, 0,
-- 
2.43.0


WARNING: multiple messages have this Message-ID (diff)
From: Luca Casati <luk00casati@gmail.com>
To: linux-wireless@vger.kernel.org
Cc: johannes@sipsolutions.net, arend.vanspriel@broadcom.com,
	b43-dev@lists.infradead.org, Luca Casati <luk00casati@gmail.com>
Subject: [PATCH wireless-next 3/5] b43: N-PHY: fix rev3+ RSSI calibration
Date: Mon, 26 Oct 2026 19:15:41 +0100	[thread overview]
Message-ID: <20261026181543.77763-4-luk00casati@gmail.com> (raw)
In-Reply-To: <20261026181543.77763-1-luk00casati@gmail.com>

Three bugs in b43_nphy_rev3_rssi_cal():

- On rev7+ the selected VCM was written using the loop counter (8 after
  the search loop) instead of vcm_final; the 3-bit field turned that
  into VCM 0 on every rev7+ PHY.
- The distance used I*I + Q*I instead of I*I + Q*Q (brcmsmac
  wlc_phy_rssi_cal_nphy_rev3()).
- Negative W1/W2 offsets were rounded as -(abs(x + 4) / 8) instead of
  -((abs(x) + 4) / 8).

Found and fixed with the help of an AI coding assistant (Claude Opus 5.5),
by comparing mmiotraces of b43 and wl on the same card.

Signed-off-by: Luca Casati <luk00casati@gmail.com>
---
 drivers/net/wireless/broadcom/b43/phy_n.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c
index cabf61870..44769dbb7 100644
--- a/drivers/net/wireless/broadcom/b43/phy_n.c
+++ b/drivers/net/wireless/broadcom/b43/phy_n.c
@@ -2167,7 +2167,7 @@ static void b43_nphy_rev3_rssi_cal(struct b43_wldev *dev)
 				continue;
 			for (vcm = 0; vcm < 8; vcm++) {
 				currd = results[vcm][i] * results[vcm][i] +
-					results[vcm][i + 1] * results[vcm][i];
+					results[vcm][i + 1] * results[vcm][i + 1];
 				if (currd < mind) {
 					mind = currd;
 					minvcm = vcm;
@@ -2179,12 +2179,16 @@ static void b43_nphy_rev3_rssi_cal(struct b43_wldev *dev)
 			results_min[i] = minpoll;
 		}
 
-		/* Select the best VCM */
+		/*
+		 * Select the best VCM. (This used to write the loop counter,
+		 * 8, which the 3-bit field turned into VCM 0 on every rev7+
+		 * PHY.)
+		 */
 		if (dev->phy.rev >= 7)
 			b43_radio_maskset(dev,
 					  core ? R2057_NB_MASTER_CORE1 :
 						 R2057_NB_MASTER_CORE0,
-					  ~R2057_VCM_MASK, vcm);
+					  ~R2057_VCM_MASK, vcm_final);
 		else
 			b43_radio_maskset(dev, r | B2056_RX_RSSI_MISC,
 					  0xE3, vcm_final << 2);
@@ -2219,7 +2223,7 @@ static void b43_nphy_rev3_rssi_cal(struct b43_wldev *dev)
 				if (j / 2 == core) {
 					offset[j] = 232 - poll_results[j];
 					if (offset[j] < 0)
-						offset[j] = -(abs(offset[j] + 4) / 8);
+						offset[j] = -((abs(offset[j]) + 4) / 8);
 					else
 						offset[j] = (offset[j] + 4) / 8;
 					b43_nphy_scale_offset_rssi(dev, 0,
-- 
2.43.0


_______________________________________________
b43-dev mailing list
b43-dev@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/b43-dev

  parent reply	other threads:[~2026-10-26 18:15 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-26 18:15 [PATCH wireless-next 0/5] b43: N-PHY: fix calibrations on rev7+ (BCM43228) Luca Casati
2026-10-26 18:15 ` Luca Casati
2026-10-26 18:15 ` [PATCH wireless-next 1/5] b43: N-PHY: fix the TX tone sample table Luca Casati
2026-10-26 18:15   ` Luca Casati
2026-10-26 18:15 ` [PATCH wireless-next 2/5] b43: N-PHY: fix TX IQ/LO calibration Luca Casati
2026-10-26 18:15   ` Luca Casati
2026-10-26 18:15 ` Luca Casati [this message]
2026-10-26 18:15   ` [PATCH wireless-next 3/5] b43: N-PHY: fix rev3+ RSSI calibration Luca Casati
2026-10-26 18:15 ` [PATCH wireless-next 4/5] b43: N-PHY: wait for the first 2057 RC calibration run Luca Casati
2026-10-26 18:15   ` Luca Casati
2026-10-26 18:15 ` [PATCH wireless-next 5/5] b43: N-PHY: add the missing override to the rev7 TX_PU command Luca Casati
2026-10-26 18:15   ` Luca Casati
2026-10-28 18:12 ` [PATCH wireless-next 0/5] b43: N-PHY: fix calibrations on rev7+ (BCM43228) Rosen Penev
2026-10-28 18:12   ` Rosen Penev
2026-10-29  7:13   ` Johannes Berg
2026-10-29  7:13     ` Johannes Berg

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20261026181543.77763-4-luk00casati@gmail.com \
    --to=luk00casati@gmail.com \
    --cc=arend.vanspriel@broadcom.com \
    --cc=b43-dev@lists.infradead.org \
    --cc=johannes@sipsolutions.net \
    --cc=linux-wireless@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.