| Message ID | 20241025-mcp251xfd-fix-coalesing-v1-1-9d11416de1df@pengutronix.de (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [can] can: mcp251xfd: mcp251xfd_ring_alloc(): fix coalescing configuration when switching CAN modes | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Series ignored based on subject |
On Fri, Oct 25, 2024 at 04:47:19PM +0200, Marc Kleine-Budde wrote: > Since commit 50ea5449c563 ("can: mcp251xfd: fix ring configuration > when switching from CAN-CC to CAN-FD mode"), the current ring and > coalescing configuration is passed to can_ram_get_layout(). That fixed > the issue when switching between CAN-CC and CAN-FD mode with > configured ring (rx, tx) and/or coalescing parameters (rx-frames-irq, > tx-frames-irq). > > However 50ea5449c563 ("can: mcp251xfd: fix ring configuration when > switching from CAN-CC to CAN-FD mode"), introduced a regression when > switching CAN modes with disabled coalescing configuration: Even if > the previous CAN mode has no coalescing configured, the new mode is > configured with active coalescing. This leads to delayed receiving of > CAN-FD frames. > > This comes from the fact, that ethtool uses usecs = 0 and max_frames = > 1 to disable coalescing, however the driver uses internally > priv->{rx,tx}_obj_num_coalesce_irq = 0 to indicate disabled > coalescing. > > Fix the regression by assigning struct ethtool_coalesce > ec->{rx,tx}_max_coalesced_frames_irq = 1 if coalescing is disabled in > the driver as can_ram_get_layout() expects this. > > Reported-by: https://github.com/vdh-robothania > Closes: https://github.com/raspberrypi/linux/issues/6407 > Fixes: 50ea5449c563 ("can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode") > Cc: stable@vger.kernel.org > Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Reviewed-by: Simon Horman <horms@kernel.org>
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c index e684991fa3917d4f6b6ebda8329f72971237574e..7209a831f0f2089e409c6be635f0e5dc7b2271da 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c @@ -2,7 +2,7 @@ // // mcp251xfd - Microchip MCP251xFD Family CAN controller driver // -// Copyright (c) 2019, 2020, 2021 Pengutronix, +// Copyright (c) 2019, 2020, 2021, 2024 Pengutronix, // Marc Kleine-Budde <kernel@pengutronix.de> // // Based on: @@ -483,9 +483,11 @@ int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv) }; const struct ethtool_coalesce ec = { .rx_coalesce_usecs_irq = priv->rx_coalesce_usecs_irq, - .rx_max_coalesced_frames_irq = priv->rx_obj_num_coalesce_irq, + .rx_max_coalesced_frames_irq = priv->rx_obj_num_coalesce_irq == 0 ? + 1 : priv->rx_obj_num_coalesce_irq, .tx_coalesce_usecs_irq = priv->tx_coalesce_usecs_irq, - .tx_max_coalesced_frames_irq = priv->tx_obj_num_coalesce_irq, + .tx_max_coalesced_frames_irq = priv->tx_obj_num_coalesce_irq == 0 ? + 1 : priv->tx_obj_num_coalesce_irq, }; struct can_ram_layout layout;
Since commit 50ea5449c563 ("can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode"), the current ring and coalescing configuration is passed to can_ram_get_layout(). That fixed the issue when switching between CAN-CC and CAN-FD mode with configured ring (rx, tx) and/or coalescing parameters (rx-frames-irq, tx-frames-irq). However 50ea5449c563 ("can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode"), introduced a regression when switching CAN modes with disabled coalescing configuration: Even if the previous CAN mode has no coalescing configured, the new mode is configured with active coalescing. This leads to delayed receiving of CAN-FD frames. This comes from the fact, that ethtool uses usecs = 0 and max_frames = 1 to disable coalescing, however the driver uses internally priv->{rx,tx}_obj_num_coalesce_irq = 0 to indicate disabled coalescing. Fix the regression by assigning struct ethtool_coalesce ec->{rx,tx}_max_coalesced_frames_irq = 1 if coalescing is disabled in the driver as can_ram_get_layout() expects this. Reported-by: https://github.com/vdh-robothania Closes: https://github.com/raspberrypi/linux/issues/6407 Fixes: 50ea5449c563 ("can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode") Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> --- drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- base-commit: 9efc44fb2dba6138b0575826319200049078679a change-id: 20241010-mcp251xfd-fix-coalesing-f373066dd42e Best regards,