Commit 1788cf6a91 ("tty: serial: switch from circ_buf to kfifo")
introduced an error in the TX DMA handling for 8250_omap.
When the OMAP_DMA_TX_KICK flag is set, the "skip_byte" is pulled from
the kfifo and emitted directly in order to start the DMA. While the
kfifo is updated, dma->tx_size is not decreased. This leads to
uart_xmit_advance() called in omap_8250_dma_tx_complete() advancing the
kfifo by one too much.
In practice, transmitting N bytes has been seen to result in the last
N-1 bytes being sent repeatedly.
This change fixes the problem by moving all of the dma setup after the
OMAP_DMA_TX_KICK handling and using kfifo_len() instead of the DMA size
for the 4-byte cutoff check. This slightly changes the behaviour at
buffer wraparound, but it still transmits the correct bytes somehow.
Now, the "skip_byte" would no longer be accounted to the stats. As
previously, dma->tx_size included also this skip byte, up->icount.tx was
updated by aforementioned uart_xmit_advance() in
omap_8250_dma_tx_complete(). Fix this by using the uart_fifo_out()
helper instead of bare kfifo_get().
Based on patch by Mans Rullgard <mans@mansr.com>
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Fixes: 1788cf6a91 ("tty: serial: switch from circ_buf to kfifo")
Link: https://lore.kernel.org/all/20250506150748.3162-1-mans@mansr.com/
Reported-by: Mans Rullgard <mans@mansr.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250522053835.3495975-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The console dimension and cursor position are available through the
/dev/vcsa interface already. However the /dev/vcsa header format uses
single-byte fields therefore those values are clamped to 255.
As surprizing as this may seem, some people do use 240-column 67-row
screens (a 1920x1080 monitor with 8x16 pixel fonts) which is getting
close to the limit. Monitors with higher resolution are not uncommon
these days (3840x2160 producing a 480x135 character display) and it is
just a matter of time before someone with, say, a braille display using
the Linux VT console and BRLTTY on such a screen reports a bug about
missing and oddly misaligned screen content.
Let's add VT_GETCONSIZECSRPOS for the retrieval of console size and cursor
position without byte-sized limitations. The actual console size limit as
encoded in vt.c is 32767x32767 so using a short here is appropriate. Then
this can be used to get the cursor position when /dev/vcsa reports 255.
The screen dimension may already be obtained using TIOCGWINSZ and adding
the same information to VT_GETCONSIZECSRPOS might be redundant. However
applications that care about cursor position also care about display
size and having 2 separate system calls to obtain them separately is
wasteful. Also, the cursor position can be queried by writing "\e[6n" to
a tty and reading back the result but that may be done only by the actual
application using that tty and not a sideline observer.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Link: https://lore.kernel.org/r/20250520171851.1219676-3-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is comprised of 3 aspects:
- Take note of when applications advertise bracketed paste support via
"\e[?2004h" and "\e[?2004l".
- Insert bracketed paste markers ("\e[200~" and "\e[201~") around pasted
content in paste_selection() when bracketed paste is active.
- Add TIOCL_GETBRACKETEDPASTE to return bracketed paste status so user
space daemons implementing cut-and-paste functionality (e.g. gpm,
BRLTTY) may know when to insert bracketed paste markers.
Link: https://en.wikipedia.org/wiki/Bracketed-paste
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250520171851.1219676-2-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The generated table maps complex characters to their simpler fallback
forms for a terminal display when corresponding glyphs are unavailable.
This includes diacritics, symbols as well as many drawing characters.
Fallback characters aren't perfect replacements, obviously. But they are
still far more useful than a bunch of squared question marks.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250507141535.40655-5-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Systems that issue PCIe hot reset requests during a suspend/resume
cycle cause PCI1XXXX device revisions prior to C0 to get its UART
configuration registers reset to hardware default values. This results
in device inaccessibility and data transfer failures. Starting with
Revision C0, support was added in the device hardware (via the Hot
Reset Disable Bit) to allow resetting only the PCIe interface and its
associated logic, but preserving the UART configuration during a hot
reset. This patch enables the hot reset disable feature during suspend/
resume for C0 and later revisions of the device.
Signed-off-by: Rengarajan S <rengarajan.s@microchip.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250425145500.29036-1-rengarajan.s@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the Unicode screen buffer, we follow double-width code points with a
space to maintain proper column alignment. This, however, creates
semantic problems when e.g. using cut and paste.
Let's use a better code point for the column padding's purpose i.e. a
zero-width space rather than a full space. This way the combination
retains a width of 2.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250417184849.475581-11-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The generated table maps base character + combining mark pairs to their
precomposed equivalents using Python's unicodedata module.
The default script behavior is to create a table with most commonly used
Latin, Greek, and Cyrillic recomposition pairs only. It is much smaller
than the table with all possible recomposition pairs (71 entries vs 1000
entries). But if one needs/wants the full table then simply running the
script with the --full argument will generate it.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250417184849.475581-8-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Zero-width Unicode code points are causing misalignment in vertically
aligned content, disrupting the visual layout. Let's handle zero-width
code points more intelligently.
Double-width code points are stored in the screen grid followed by a white
space code point to create the expected screen layout. When a double-width
code point is followed by a zero-width code point in the console incoming
bytestream (e.g., an emoji with a presentation selector) then we may
replace the white space padding by that zero-width code point instead of
dropping it. This maximize screen content information while preserving
proper layout.
If a zero-width code point is preceded by a single-width code point then
the above trick is not possible and such zero-width code point must
be dropped.
VS16 (Variation Selector 16, U+FE0F) is special as it typically doubles
the width of the preceding single-width code point. We handle that case
by giving VS16 a width of 1 instead of 0 when that happens.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250417184849.475581-4-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 74045f6658.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 2acaf27cd7.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit e88391f730.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 26c94eb484.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 3a1ab63aa0.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit f2347b0cdf.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 54af55b990.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit cd6937d42b.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 119ff0b0f4.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit c7cb5b0779.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 547f57b88d.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit b35f7a773c.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 8bfabff0bf.
A new version of the series was submitted, so it's easier to revert the
old one and add the new one due to the changes invovled.
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
